If you're attracted to the girl then nothing wrong going out with the ML or WL. You never know you might have lots of fun and enjoyment with the girl. Some girls want to go out and if they like what they see, they will not be too shy in asking. However, be careful in that she doesn't take you for a ride and expect that you pay for everything with nothing in return from her. In addition, there are many young girls looking for sugardaddy arrangements. Whether you want to spend considerable amounts of money on one girl is up to you but with many girls out there, it would not be a good decision in the long run.