Paranoia.
These things could be anything, you have been looking at her and watching her too much.
1. Slightly larger hands and feet. Go have a look at other women you aren't smitten with. You will see a large variety.
2. Not exactly a feminine gait. You met her at a gym and she is in her early thirties and she's hot! Girls at that age who are hot generally do a lot of working out, which means more lean muscle mass, which generally means stiffer movement. Young hot women who are naturally graceful and move in a feminine way don't have much muscle mass to get tight and stiff.
3. Paranoia. In her thirties, hot with no major relationships. Look around again. You will find other women in the same boat. She might have had five year boyfriends or what not, but doesn't talk about it.
4. Does not APPEAR to have any close friends. Despite your chemistry, you see her at the gym, a place a lot of people go to work out and let go. Go out and talk to some other women, in their thirties or whatever, some people can get by with little social contact in general.
None of these things indicates anything. If you ask you will lose either way. You have been played by whoever said that to you. If it was true, and the other woman knew, what did she have to gain by telling you?