I think I might have ED?

i'm a 17 year old guy and have just recently became ually active, however, i've been having some serious issues with my s... first off, i have a really hard time getting it up when i want to, but i'm hard as a rock just cuddling or something stupid haha.. this is probably psychological and because of some sort of anxiety but i swear i feel calm, almost too calm, ha.. then once i finally get it up i only last like 20-30 seconds at best before i lose control. she seems really understanding and shes much more experienced than i am, but im just letting it get to me.. like what if i never learn to control it.. do yall have anything to say about this? thanks