"I am wondering what type of HIV risk there is for this type of encounter." Zero.
"Is this even something to worrry about?" No.
"Was there any legitimate chance of contracting any other STD?" Nope. Extremely low risk of herpes or HPV, given the skin-skin contact with her genital secretions. But this also is much too low a risk to worry about.
"I spoke with the girl in question and she mentioned that she tests regularly and is fine, but I still am nervous about this." Why? Most people don't lie about such things when asked directly.
Mellow out. Don't get tested for HIV or any other STD on account of this event. Just go on with life.
Good luck-- HHH, MD
HHH, MD