I am 13, I had intercourse with my boyfriend, now I feel really bad

Okay so I'm 13 and my boyfriend is 15, 16 in April. I met him in November of 2013 and have been going out with him since January 2014, so 14 months now. The day I came back from holiday in late August, I stayed over at his house because I missed him so much, (I was gone for three weeks.) We were just cuddling and then he started kissing me, and touching me. I knew what was going to end up happening and I was a little scared but I didn't tell him. Before anything got any further he kept asking me if I was okay and I told him yes, but when it came to it it hurt to much and I asked him to stop and he said yes of course, before any of you assume he was forcing me into anything. Also, if any of you think he's only with me because he can't get a girl his own age, it isn't true because he thought I was older when we first met and I didn't actually tell him how old I was until he asked me out. Then on our 1 year anniversary in January we went out for dinner and when we got back we were yet again cuddling in bed and yet again things escalated but this time I didn't tell him to to stop, and I had sex with him, he made sure I was okay and all that but yeah. Now it's March and I think about what happened that night, it's not like I regret it but I feel really bad, like I should've waited. And now every time we kiss I always get super nervous and I just stop acting like myself, because I keep thinking it'll lead to something else and we'll have sex again. It's not that I'm scared of him either, I really don't know what it is. I told my closest friend and she swore she wouldn't tell anyone, although I dk t know if she had kept that secret. I just feel like a s***, why did I do it at such a young age you know? And please do not say I'm stupid or anything like that, yeah maybe I am a little foolish but I can't turn back time and change what happened. I actually think I am very mature and sensible for my age but some of you may think different. I just want to know if any one else feels the same, like are you in the same position as me or have you experienced it before?