You still couldn't get up while you were going down?
Do that first, they like that fist, start with 4play like that and don't even pressure yourself to get up in the first place.. Just enjoy pleasing her, and I bet you will get it, and if not just do a good job of that and all is well.. Take it slow and easy, time is good..
I bet it's the pressure or nervousness..
at the op this is very close to what you should be doing.
here is why muff diving allows the girl to have orgasms.
if giving the girl orgasms is the number one priority for you the girl will reciprocate if she is worth while.
hard ons are not as necessary as you think for orgasms or pleasure on a guys part.
if sex is pleasure based for both of you oral sex works both ways.
If you are not into oral sec and your girl friend in not into oral sex. you won't realize full sexual pleasure as a couple.
I been with a few women in my life and only one girl I was with was intercourse or oral sex for her orgasms. the other girls all preferred to receive oral sex for their best pleasure.
Once you realize she really likes to get and give oral sex hard-ons will show up more naturally.
Good luck sorting this out.
and do not watch porn for a month. Instead close your eyes and think about giving the new girl friend solid long powerful muff jobs.
I do assume at 32 you are healthy and not 100 pounds over weight.