Is 35 too young to be a MILF?
I always thought MILF as a more of a subjective term.
To me MILF is more of a fantasy of being with an older woman (your own mother's age), in a more motherly role, but not in a Freudian/Oedipus type of thing.
A MILF to one person would be a GILF to another.
Unless one believe that having kids makes a woman somehow less attractive, that those that are still attractive are rare.
So 35 would be a MILF to a 16yr old.