You are talking about shemale. Let me tell you that many men want to have sex with shemale and red light area vastly demands shemale and charge good amount of money for providing shemale.
If you want to have sex with her then you have to fuck her anus but you need to be clear, whether she will ask her for the return and wants you to bang down for her.
Therefore, if you are ready to offer your anus to her then there is nothing wrong in having sex with her. She can demand many things like, you can fuck her anus but in return, you need to give her blowjob.
You can fuck her ass and in return, you need to offer her your ass. She can allow you to have sex with her and in return, you need to give her good amount of money for her service so before planning sex with her, discuss with her what she expects from you.
If you are comfortable in fulfilling her demands, then go and have great experience. Use lots sex cream to make sex easy and I am sure she knows how to have painless sex. However, if you are uncertain whether to go ahead or not then, I would like to tell you refrain yourself since you are not fully confident.