LORA weight 0.9 works great, but feel free to adjust the strength to your liking
Prompts that I usually used:
Older version:
aMei, long hair, white hair, braid, hair over one eye, braided ponytail, purple eyes, dark purple dress, long sleeves, puffy sleeves, turtleneck dress, wide leg jumpsuit pants
Younger version:
bMei, white hair, ponytail, parted bangs, hair ornament, scrunchie, purple eyes, black shirt, grey necktie, dark purple skirt, long skirt, high-waist skirt