5 years is good! I was worried you were going ot say like 15 years or something. But really age difference is all you are comfortable with. I would be kind of careful with anyone under 20... mostly for legal reasons....
5 years is a pretty good age difference. my parents are about 6 years. me and my guy are only 11 months though.
Just seems where you are comfy with!
You probably would have been okay if you hadn't started appologizing. Tara said something good: just ask her out. like would you like to meet for drinks after work? or have lunch together... stuff like that .