I would say no for 2 reasons:
1) she might want to make it into a grow room, which will wreck your unit - the humidity and potential water on the floor, plus the smell, etc., will possibly do major damage; and
2) tenants who start wanting to change things are never-ending high maintenance tenants and you're better if they leave. Been there many times. Learned the hard way to say no and to see red flags during the initial walk-through. Odds are that this is not the first time this tenant has asked for some kind of change or favor, right?
The one I had like that started at the walk-through asking if we'd change up the walk-in closet that the unit already had that was enormous - can we extend one of the rods and take out the shelves on that end so the rod is longer? It never ended after the owner agreed to this request. In the future I learned to just say no right then and there.
She later wanted room darkening curtains which the owner said yes to - I told him not to (he would come on Saturdays to do maintenance and the tenants learned to go around me and just ask him for stuff. I told him to send them to me, but he was too nice - but it just gave us both more work).
Then, she said she could smell smoke and wanted me to go figure out who it was. I said no, I wasn't going to go invading tenants' apartments, but if she ever actually saw someone smoking to let me know. She actually complained to the owner. He confronted me with her standing right there smirking. I said no, it would be an invasion of privacy and I wasn't going to do it. I basically had to dare my boss to fire me over it. He chose to keep me.
She was still there when I left with her never-ending drama and demands.
You just have to make a rule. It's easier to say no to people if you know what your rules are. So, this was the rule I learned to have and I suggest you have, too.
"I don't change any units I have. Sorry if you don't like it the way it is, and I totally understand if you want to move. If you want to give me 30 days notice, let me know and I will work with you on your move-out date. But, I don't make changes to my units." And when they start arguing and giving you their story or sales-pitch, just rinse, repeat.