There are many girls that have their own personal age restrictions. I am really uncomfortable with under 20 and prefer over 25. It would be in your (anybodies) best interests to read ads, and then double check by telling the girl at the time of booking your age. You may get asked for ID at massage parlors and some independents to prove you are legal.
I was watching a movie called personal services, which is based on a true story. The madam got her 16 year old son a session with one of her girls. Then right after, she gave her dad the same girl, lol I wouldn't have been able to do it, lol