How important is physical size in law enforcement?:
Go out and join law enforcement. If you have the education and the training, you should do fine.

However, be aware that the people who you will deal with are living a different reality than you and me. They operate on the law of the jungle. The strong survive and power means everything. I happened to be a tall, strong law enforcement officer and I rarely have a suspect fight me. They have told me my size made them think twice before fighting. If you are small in nature, you may have to fight more. And keep in mind, most of the time you will have one or more back-up officers with you. Citizen who see us three or more deep arresting someone don't realize that we bring a lot of officers out to avoid fights. We know the nature of these people.

With that said, all of the smaller officers I know are fully capable of doing this job. Just be aware of what you might be getting in to.