In a proper healthy relationship it should bring you closer.
Or it can lead to the boy losing interest in you and the end of the relationship. Because they've gotten what they want - another notch on their bedpost and they want to move on to their next conquest.
Or it could be that you discover that you are sexually incompatible, which is the death knell of a happy relationship.
At the age of 16 it's possible but rather unlikely that your relationship will last until you are 25 years old.
And 16 is a bit young to be getting involved in sex. Mainly due to the lack of maturity from your boyfriend. He's a 16 year old boy! He's not going to be mature! He's going to do and say a certain amount of things that are hurtful and annoying to you because h'es immature.
If you get pregnant that might draw you closer to each other, or slightly more likely, he'd want to run a mile because he doesn't want to be a dad at the age of 16 or 17.
If you do go ahead with the sex, go in with your eyes wide open. Take the contraception very seriously. Take the prospects that this might be a serious long term relationship with a huge pinch of salt and treat your time with him as a bit of fun and of you starting your apprenticeship in finding out what relationships are all about: the recruitment and the retention.