My family dont know about my boyfriend do I tell them?

Ok so I'll try explain it from my way of thinking. My parents well mainly my mum wont let me have a boyfriend, I am 19 nearly 20 for two reasons: 1) is becuase my ex was really bad too me when I was with him I changed into a horrible person as I brought all the issues from our relationship home, such as insteda of getting angry at him I took it out on my mum ( not on purpose), he also cheated on me, humiliated me by putting it on the internet and was vile when he broke up with me calling me names, saying I was nothiing more than a friend with benefits; so I was heartbroken and it took me a good 4 months too get back to normal; my mum had to put up wiht all this, she had too watch me crying myself too sleep, loose my friends, fail my exams, loose so much weight from depression that I didnt have the energy to get out of bed etc etc so I can see why she would be worried
2) she is very relgious catholic so she worries that boyfriend's = sex

Finally I decided to pick my self up so about 3 months ago I went out for a girls night out where we got chatting to a group of guys who were 24-28 they were really chatty nothng happend but I swapped numbers with this one lets call him Bob, he paid for my taxi home etc etc. We were texting quite alot when he asked me on a date, too which I lied to my mum and said i was working as anytime i mention boys now all she says is' here we go again, I dont have the energy to put up with you getting hurt you cant have a boyfriend', I had a great date with him we had a few more dates ( non of which my mum knew about ) things progressed fast tract 2 months down the line and he asked me too be his girlfriend, too which I said yes as I think he is different from my ex im not sure, but he doesnt seem like the type of guy to cheat or hurt me. So I go round his house/ on dates about once a week however I have to lie to my mum and say im at work or round a girlfriends house I tried to mention him to her saying I met him on a night out and i really liked him could I go on a date and she pointblank said 'no you cant go on a date with him, if you even consider having a boyfriend I will kick you out of this house and disown you shut up this conversation is over'... I want too be with this guy he is mending my broken heart and makes me very happy, where other aspects such as my home life are terrible and unhappy, he is the one thing that puts a smile on my face. I go to uni in 8 months where if im still ith him obs he can come to stay and she wont have to know anything about it. BUt until then I dont know what to do I feel sosooo guilty for lying to her and not telling her about him but then on the other hand I know that if I tell her she will go mental and ban me from seeing him by taking my car awayu or physically locking me in the house; if I tell her she will make my life hell and I have a feeling that the strain will be too much on our relationship/ he will think its nuts that im 19 and not allowed a boyfriend and break up withme so what im asking is : is it ok to lie to my mum aboiut my boyfriend until uni?

Just tell them, what's the worst can happen?