Does becoming sexually active effect your cycle?

Now reading that title I don't want you to think I'm just another person the American sexual education system has failed. Before last week I hadn't been sexually active in any regard. I hadn't ever masturbated either. About three weeks ago my boyfriend started fingering me and about last week we started having sex. I'm very paranoid about getting pregnant which is why we use condoms and withdrawal ( I know these two are not perfect and we won't always rely on them but for our first time it worked quite well).