So basically this girl came over to watch some movies which eventuelly led to sex apart from the problem that when the moment came I couldn't get a full on erection.(about 60% or so at times so no sex happened)

This was obviously extremly embarassing, especially because I am looking to potentionally get into a LTR with her. What would you do in my situation? Just normally text her as if nothing happened?Apologize? Is it a big deal?