It really depends on your school district and when the cut off is. She'd be barely 5. If you don't think she's ready you can always have her go to preschool or preK for a year. A lot would depend on her social skills, whether she knows her alphabet and numbers, can write her name, knows her shapes and colors, things like that. Talk with your local school and get their feedback but go with your instincts too. You know what's best for her.
Your school district has cutoff days for kindergarten. September is right at that point, and she would be the youngest in the class - not a good thing.
Wait a minute - just did the math. I think she needs to be 6, not 5 at that time. I would get her in preschool for at least one year, and possibly two depending on the preschool teacher's opinion.