birth control

Hi, I wanna ask you guys for advice, I have my boyfriend and we are starting to have sex, we did it the first time and we didn't use condom but he didn't cum inside of me or pulled out, he was doing it and then took it out and came like 10 mins after nowhere near my vagina and well he just wanted to be cautious and got me the Plan B pill and then the other 3 times we've done it has been with condom, however, I wanna have birth control just so we won't be worrying about anything, don't get me wrong I will have him use protection too but I rather be cautious in 2 ways than just 1 and we'll the problem is my mom is very very strict, she doesn't wanna take me to the doctors to have me checked and find out which ones to use even though I asked her to do t because I'm irregular so that right there are like 3 reasons for me to start taking them but she thinks I'm too young and she even had problems with him but it's all easing up so how do you think I should tell her or convince her because he said he could get me the pills but I read you should check yourself to know which ones to take so I dont know what to do, I'm 16 by the way, what do you think ?