She probably did not have the figure of a teenager by the time she died but as she was a mother several times over that would not be unexpected. As for fat, probably not.
From the ancient coins I've seen, she wasn't a raving beauty, but she wasn't ugly either and supposedly she was extremely intelligent, well read, charming, and yes, charismatic.
Though older when Antony fell mightily for her, as well as a mother, she must have had enough allure, charm, and whit to have enticed him so thoroughly.