Did I fuck up by saying I love you?

Been seeing this autistic girl for 3 months and said i love you during making out that lead to sex. It literally just slipped out and i thought wtf as the words were leaving my mouth. i had no intention of saying it going into the interaction. Neither of us acknowledged it after and the night went well but no doubt she thought that was weird. How do I recover from this is in a cool and non-chalant way?