I’d say most of the late onset tattoos, especially after a long marriage is a way for them to “break out of the mold”, feeling footloose and fancy-free after a long relationship. You said she’s got a great physique, and sometimes it’s about wanting to show off their bodies.
Unlike many here, I do not feel that a few discrete tats on a chick is a red flag. Now, it’s my personal opinion that sleeves and visible tats are more about attention getting mechanisms than anything else.
If she’s a gym bunny or has many much younger female friends it may just be a cultural thing. Women, by nature are joiners and affected often by peer groups and trends.