I have a fic about that ☝🏼

But i mean, she might have feel incredibly free, physically and mentally. I believe it was a decision on her own totally, no one like pressured or suggested it, she simply looked herself at the mirror and said "Okay, no more."

(It is my headcanon too that Odalia was the one who obligue her to keep it long, just like she asked Amity to dye hers green. Sometimes I think what she forced Edric to do, probably not letting him wear his glasses).