Really embarrassed/unattractive because of small boobs

So I’m 19 and my boobs are quite small- like an A/B cup depending on the bra... While I’ve always known that they’re small and was self-conscious about that from time to time, I could always wear a push-up or just not care about it too much.

The problem is that for the 1st time in my life I’ve started dating this really sweet and genuinely caring guy.. (I’ve never been fully naked in front of any guy before, just did different stuff with our clothes still on.)

So yesterday we were making out in his car and for the 1st time he started putting his hand closer to my chest/boob area.. I was totally fine with that, but then I literally started freaking out on the inside because like...the dude was trying to grab onto something but THERE’S NOTHING THERE

I didn’t say anything and we just kept making out, but I’ve literally never felt more unattractive and undesirable than at that moment.. Things between us are really starting to get serious and I’m sure in the future a moment will come when we’ll have sex...

Idk ladies❤️i guess I’m just asking for any advice/experience/your bf’s perspectives on small boobs etc❤️