Teen sex

Me and my boyfriend are both 15, he’s a freshman and I’m a sophomore, but he has a lot more experience than me, he lost his virginity over a year ago. He respects my boundaries and really loves me, and we make jokes about eventually having sex a lot, but I’m a little scared I’m being serious. I know that sounds dumb but when I’m with him I can’t control myself like most hormonal teenagers act, but I know in my heart I’m not ready for that. What do I do?