Higher sex drive than I thought?

Every time I hang out with my boyfriend I get horny, and not just slightly...I’m talking break a sweat, aching horny. I took pride in having a low sex drive when we first started dating and so did he (of course we’re both underage, but I’d rather not say specifically how old we are). But every time we do something REMOTELY sexual like I accidentally straddled him last weekend, he freaks out and says that he doesn’t wanna be like that yet because it just gives him anxiety, while I’m there thinking “actually, I liked it” it’s not a matter of “should I drop him or not”, but it’s more how do I explain to him how I feel without putting pressure on him?