What does it mean if an older woman tells you she'd want you if she were your age?

Exactly 2 years, 6 months 3 weeks and 6 days after the original post.

Is that in your estimation the optimum time to wait between receiving a compliment and asking them out?

As a bonus, you would qualify for the early bird special.

When an older woman expresses that she would want you if she were your age, it could imply a sense of admiration or attraction towards you. This statement suggests that she finds qualities in you that she appreciates or finds appealing, possibly hinting at a desire for a connection or relationship.