scared to have sex again? it's been nearly 3 years

So I lost my virginity when I was 15 to my boyfriend we broke up not long after, I now feel as though I was too young, but at the time I felt like I loved my boyfriend and it was the right choice. But I do not regret it. now 17 nearly 18 I haven't had sex since, but I feel REALLY nervous even thinking about having sex again. I'm seeing this boy and I feel like we may have sex but I'm just terrified. I don't know what it is but maybe I'll feel different when I know this boy better and feel more comfortable around him. Anyone else experienced this?