How to proceed (potential for awkwardness)

Cliff notes

I am 27 and work out at my alma matter's gym (nicest gym I have ever been in, not because of the hot co eds hah)

Not sure what got into me because I never do this but there was this girl working out near us that was incredible - perfect 10.

For what its worth (not much) - she looked a little older. Not sure though.

I walk up to her and ask her if she would like to grab a cup of coffee sometime to which she accepted...

This was yesterday (Saturday) - I was thinking about texting her tomorrow (Monday) and asking if she wanted to still grab a cup of coffee on Tuesday... Should I ask her to go in the morning? evening? Lunch even?

I am really afraid of her getting there and being like "ya I am 19"... I would feel really awkward obviously. If she was in that age range and she found out I was 27, do you think she would think I was a psycho?

Thoughts on this situation?