If you are truely phenomenal I'd say you may not be too old to go pro, but I'd also say temper your expectations until you've had some experience. Most people who get into cycling as a career usually start pretty early in life, those who get into it later usually come with a pretty distinguished background in some other endurance sport (running, rowing etc.) Women, I think, tend to have slightly longer careers than men, who mostly reach their peak in their mid 30's, but even at that it doesn't leave too much time to develop as an athlete. It's more than just physical ability too. Cycling really is a mental and tactical team sport. It's been called chess on wheels for a good reason and it can take time to learn the intricacies.

Also few women, especially here in the US are able to support themselves solely with a career in cycling. Many, even in the elite ranks, still have day jobs. It's not an easy life and unless you could make your way up to the very top ranks of professionals, it's highly unlikely you would ever make much money doing it. It takes a really dedicated athlete, who really loves the sport to be willing to make the sacrifices that are needed to pursue it professionally.