@harmonica,
Earlier I posted this in a sincere attempt to offer the point of view of a 21 year old dating or thinking about seeing a 37 year old man. I'll repost :
This young woman is only a few years out of high school and maybe hasn't finished college. Her most vivid memories are of the things and activities younger people share at this time in their life. I'm concerned that you worry how this age difference is perceived by others but more so that you feel jealousy and insecurity when she talks about her recent past. This may not wind up being a good relationship for you unless you can get past those obstacles.
Just also be aware that this young woman may occasionally feel out of her depth when she meets your co-workers, friends and relatives. You obviously have control over your conversations and behaviors but people tend to remark on age differences (her side and your side) you need to figure out how you and she are going to respond. Just try to remember that you were a teenager before she was born so your teen and childhood memories are going to be totally foreign to her and hers totally foreign to you. It's not fair for either of you to resent each others experiences just because they happened at different times.
That's just the advice I would give anyone contemplating a new relationship, provided they asked and really wanted my viewpoint. You seem to already feel jealous about her, jealously will make you both miserable and is not a good way to begin a friendship.