Question for Christians

*no hate please*
I believe in God, but I'm not sure if I'm a Christian. I try not to, but I cuss sometimes. I'm 19 and have sex with my boyfriend. But I go to church frequently. I know when you die it's either heaven or hell. And quite frankly, I'm not sure where I would end up, but I don't want to end up in hell!! So basically, my question is, what can I do to become a "better" Christian?  Because I know that going to church isn't enough to send you to heaven. (But I also don't want to stop having sex lol)
Thank you!☺️