Orgasming

So basically I can make myself cum all the time, sometimes in a few mins and sometimes it takes a while. But I always can. The thing is I’ve hooked up with a few guys and neither of them has been able to make me cum. They both have gone down on me and I really could have cared less lol. The sex felt better than the oral. I know sometimes too it’s hard to fully relax and I feel embarrassed/awkward sometimes in sexual situations. Anyways, what I’m asking is do you think it’s their skills personally not being able to get me to orgasm OR do you think it’s me?