Hi Jenn,
It can certainly happen right away, or, depending on how long you've been on the pill, it might take a few more months for your ovulation to kick in. I know a woman your age - now the mother of a baby girl - who was on the pill for about 18 years. It took her almost a year to conceive. She thought it was because of the pill, but I don't think she had any medical reason to back that belief up.
I would say very likely. If your periods are regular and your in good general health, its just a matter of time most likely. Its a good idea to have a physical. Then you can either start charting your cycle through basal body tempurature, or you can use an ovulation predictor kit. Using both is probably the best idea. If you need any help or more info on these tools, just let me know, and I would be happy to send you more info.
Start taking extra good care of yourself now. Eat right, start a prenatal vitamen high in folic acid. If you smoke, quit now and cut down or quit drinking.
I wish you well in trying to conceive and hope it happens quickly for you!!