Ohhh boy. Oh, boy. Where to begin?
This is all I have to say after reading this entire thread.
1. You are an adult. Do what you want.
2. You do not live with your parents. You can do what you want.
3. Your parents will not find out if you have sex or not.
4. Guys do not care if you are a virgin or not. Psychologically speaking, those who care are likely to be very possessive, controlling, jealous, and sometimes insecure, so I would not recommend dating someone who cares if you are a virgin or not.
5. Your future husband, parents, and friends do not need to be told if you are a virgin or not. Just tell the truth when asked; if they judge you for being or not being a virgin at the age of 20, you should not even have them in your life.
6. If you do not want to have sex but still want sexual stimulation because you have hormones just like every other 20-year-old, masturbate. It is not dangerous and it will probably make you more comfortable with the idea of having sex.
7. Do not be afraid of having sex because of what your parents told you. Just because you have sex with someone, it does not mean that they are using you, that you are worth less than a virgin or that you have no dignity.
8. I have never even heard of a guy being able to tell if a girl is a virgin based on the tightness of her vagina.
9. A man calling you ‘second-hand goods’ is disrespectful and insulting to you as a woman, not to mention complete BS that will not ever happen. How would said man react were HE called ‘second-hand goods’ because he was not a virgin? Oh, yes, that is right; he would ‘justifiably’ (*cough*unjustifiably*cough*) beat you to a pulp for not being a submissive little doormat subservient to him. As someone else said, it is a very misogynistic thing to say. It implies that he sees you as being below him rather than his equal. If anyone ever does that or would do that, then they are not worth spending your life with.
10. Fun fact: I have never heard of anyone who has waited for marriage in real life. Your parents most likely did not wait for marriage either (unless they met on the day they married). (I am not saying people who wait until marriage do not exist; just that they are so rare OP will most likely never find one.) Do what you want before marriage because you do not even want a virgin to be your husband and it would be unfair of him to expect you to be a virgin when he would not be. (It does not matter if any of you is a virgin or not as long as you love each other anyway.)
11. Last time I checked, 42% of marriages in the UK end in marriage. That means whether you wait for marriage or not, there is a high chance of it not mattering because the divorce rate is so high. Being a virgin before the wedding night does not mean your marriage is more likely to last.
12. Not all men want to use you for sex. There are plenty of decent men out there.
13. If you do not want to be financially dependent on your father, get a part-time job (receptionist, etc), rent a flat with a person or two (basically flat-share like you are house-sharing now), and split the rent and the bills. You may not be able to earn enough for a rented flat by yourself, but two or more people can definitely do it as long as they are adults with part-time jobs.
14. Whenever your mum asks you 'Have you thought about it?' after mentioning that someone's son is single, answer that there is nothing to think about because she just mentioned that a guy is single. Being single is quite common, which means you do not have to think about marrying him just because he is single. By her logic, you would have to think about marrying EVERY SINGLE GUY just because they are single.
15. Do not marry whoever your parents want you to marry. Even if they get you engaged without your consent, you do not have to do it! It is haraam for the wali (guardian) of a woman to force her to marry someone she does not want and does not like. The Prophet himself said that a woman should not be engaged or married without her permission. As such, even by Muslim ideas, your parents cannot force you to marry without your consent, as that is haraam and the marriage would not be valid. Kindly remind them it is a sin for them to force you into marriage whenever they bring it up.
16. Your mother is a manipulative, controlling b**** and most likely has several mental problems. She also does not care about you, only about her reputation. Trust me, I know her kind.
17. So far, this has been unclear, but if you do not believe in Islam or do not agree with it, convert to Christianity/become an atheist/whatever strikes your fancy. Contrary to what the Qur’an says, you will not go to hell for not believing in Islam. Besides, have you heard of the theory that all religions actually follow the same God, just under different names?
18. To those who think OP should meet the guys her mother talks about: her mother is manipulative and controlling, so any guy the mother picks is likely to be as manipulative and controlling as her. After all, her mother would deem him unsuitable otherwise. OP wants to get rid of the controlling behaviour her mother exerts over her. Meeting the people her mother wants is most likely a terrible idea and will probably just enhance the amount of control her mother has over her, which is not what OP wants.
19. Cut off your parents from your life if you want to. You do not need to keep them in your life just because they had sex and happened to conceive you.
20. If OP is a troll: I do not care and I will still post this for anyone who might be in a similar situation.
Stay strong, OP. I am a Christian but my mother is almost the same as yours (which is why I moved out before I even became an adult). After seeing everything mentioned here, I honestly bet your 'sex talk' was basically your mother yelling at you not to have sex. Anyway, just try not to go insane and do your own thing. My suggestion is not to believe what your parents say either. Good luck.