Generally, going out or having sex with a current superior (teaching assistant, teacher, professor or boss) is a bad idea:
* Trust me, people will find out. And then that will be the only thing they think about when your name comes up. People will assume you have no talent in the classroom or on the job and are just trading sex for a leg up (pun intended).
* Also, people are going to assume that whatever your motivations, your superior will give you unfair advantages. In fact, that itself can lead to sexual harassment charges against him/her (even if you fully consented, the relationship in an important sense causes discrimination in your favor at your peers' expense).
* Next time your superior criticizes you, are you going to continue to be as objective in responding as you were before you got so close?
* What happens if it ends? Especially if it doesn't end well?
Note the term "current". Once you're out of their classes (preferably schools) or offices, and you've reached the age of consent, have a good time!