She told me she wasn't on her period, but can a squirt trigger girls' period? My nails were completely trimmed so I can't believe I inflicted any wounds to her inner vagina by scratching. Is this normal or maybe I wasn't gentle enough?

I didn't move the fingers in and out, only up and down, fast, like squirting is. Also, I held her pubic area down with my other hand like I believe is standard procedure when squirting.

She was not a virgin and her vagina was wet before and during the squirting. She didn't say it was hurting and liked it very much

She must have been on her period, but not known or it was just starting.
Another thing, I did try to put my whole hand inside her vagina, with the fingers pointing inside the vagina (not a fist), that could mean I scratched her unknowingly even with my nails trimmed