I was having a think about MILFs during the week, There I was getting a massage and HJ from a very sweet thai girl with D bolt-ons who in conversation told me the age of her one child which was in contrast to my assessment of her 29-30 age. She was 41 while I was thinking she looked and acted 29-30ish. She was very well kept.

Boilers - 41 yo, married with three kids and limited physical activity, no motivation to appear attractive
MILF - 41 yo, one kid, regular gym AND looking for a new husband. very motivated to be well presented

Age of itself is not an indication.