Well if you completed all of her sparring lessons and had talked to her about her robes then consulted Kreia, there is no need to because you can teach her to become a jedi.

Ok to be more clear:
1. Spar with handmaiden and win at least once.
2. Put your clothes on after the fight and convince handmaiden to put some clothes on.
3. She puts on her mother's robes.
4. Talk to her about her mother.
5. After that's done talk to Kreia and she will talk about handmaiden.
6. Get to the point in the conversation where you can say: "how do I train here"; Kreia tells you to complete all of her sparring lessons.
7. So finish all her sparring lessons and she will say that she can't teach you anything else and ask her if you can teach her.
8. She should say yes or something and follow up on a line about her mother or father and say that she has the force in her because her mother was a jedi.
9. She should be convinced and you teach her to be a jedi by saying some lines to her.

But the for the reason why you're not getting more influence points is unknown to me. All I know is once you can teach her to become a jedi, there really isn't much need for influence on her.

Make sure you don't spend too much time with Visas before you complete the 3 sparring sessions, she will get mad at you and then you won't be able to do anything with Handmaiden. Other than that what bama said is correct.

Are you on the light side or the dark side?

Some of the times when you think you will get influence it might trick you so keep her in your party all the time.