Oh my god you're right they're probably gonna be the only old ladies more mature women around. They probably have a weekly bridge/mahjong game in which they gossip about the birds in Aria or some dumb shit oh lord.

And yes tell her about all of your child baggage. She'll tell Toriel all about the scourge and her own shitty world. She wishes the beasts of her world just baked people pies instead of brutally murdering them.

Also her job is to murder her former friends and allies after they're too far gone to control themselves which is going to be a big hurtle when it comes to befriending someone who is ALREADY a large monster.