Hi N.,
Relaxing is fine...BUT you have to keep it up.
That means time and money.
Every three months for touch ups and regular trims.
This is a lot for a child.
So it makes sense to say no to a relaxer for a seven year old, but understand it is not the end of the world.
AND that may have to be your back up plan.
Also depending on the texture you may be able to do it twice a year or four times a year like I do for my daughter.
My daughter's hair looks beatiful and people always ask me
Black, White and Hispanic where do I get her hair done.
You have to keep a calendar of her hair appointments and make sure she gets regular trims and conditioner treatments. You have to braid it up for protection as cholrine tangles. If you think you can go to the beauty parlor one time and never go back again your daughter's hair will suffer.
Blow outs are great as well and you don't need a relaxer for it. Remember everything you're doing is to keep her hair from tangling and breaking.
Depending on your daugther's hair texture you can get it bi-weekly or monthly. Use only the shampoos, balms, combs that the beauty salon uses. All of it will be tangle free and the combs wide. Small combs are only used to make parts. Wide brushes are used to detangle. Do not wash every day or comb again after morning combing. Black hair is delicate because it is curly and breaks easily. So think curly is delicate and can't take too much pulling. They will also teach you how to keep your daugther's hair from tangling between appointments.
I think you should skip Harlem (too expensive) and go to Dominican hair dressers. At the hair dresser they will be every shade of brown and every texture of hair and they will see your daughter's hair and know what her hair needs. Remember hispanics are a mixed race people of conquering Spainards, enslaved native Indians and importing African slave labor.
Lastly, my friend is a white hispanic who married a black hispanic and though her daugther's hair is nothing like her own her daugther's hair is always beautifully managed. I have Asian friends who married black men and their daughter's hair is beautifully managed. Only White women who have mixed daugther's leave their girls hair unruly on their heads. I don't know why?
Anyway good luck.