That is totally your decision. I keep all of my cats indoors, all the time. They are always happy - which is what matters most. If you do let your cat outside, make sure she is up to date on vaccinations, has proper identification and is spayed. Be prepared for the worst if she leaves and doesnt come back for a while. That happened to cats I had when I was younger and it ended up that they were hit by cars or eaten by a wild animal.

It is risky, but many cats live happily outside.