"Student Aide" During Junior Year

I’m going into my junior year, and I’ve somehow managed to be left with a free period. I don’t want to add on an extra AP class as I’m already jam-packed, and I don’t want to take some obscure honors class that I don’t care about. So, my current AP Art History teacher has asked me to be her student aide. She says I would have a lot of time to do my own work and she’d happily write me a letter of recommendation (she’s an excellent writer; I have no doubt that the LOR would be stellar.) But how would this look to admissions…me taking a Student Aide (Executive Intern on my transcript) position?

NOTE: I’m taking a lot of dual enrollment courses, by the end of my junior year I would’ve taken 9/10 APs/AICE, and I plan to have a decently rigorous schedule senior year.

My classes:
(1. AP Language and Comp.
2. AP Physics
3.AP Comp Sci Prin
4.AP Statistics
5.AICE French

and 6. US History Honors )

Your schedule is well balanced, included all core classes and would meet any definition of ‘most rigorous’.
Therefore, from an admissions point of view you’re free to do as you please. And the option of being a teacher’s aide for a class you took and did well in + making a better recommendation possible sounds win-win.

You could do that or take a “fun” course…e.g. Photography or cooking or somethign.
You have plenty of APs…being an Aide or learnign a new skill will be fine.