Sylvia has brown, (dyed in a failed attempt to look dirty blonde) choppy, badly cut sort of hair, and chocolate-y skin. She has teal sort of eyes, and an average sort of build -- 5'1, maybe? She's a little on the chubby side.
Sylvia's constant mood while listening to someone talking is, "I feel like a fork is being scraped against a blackboard". She loves to lead, to the point where she'll get angry if something isn't going her way. Mind it -- she's not hotheaded, nor someone who'll explode in your face. She's the sort of person who likes to bottle up all anger and decide someone's good enough to be angry at, and then screech her head off at them. She's very loyal to those she believes have earned her loyalty. The list isn't particularly long. Sylvia is passionate about her opinions, and probably someone who'll be ready to bite your head off if you refuse to agree with them. She loves the idea of a first impression, and -- for some reason, prefers to be aloof when introduced to someone. Is she trying to be that mysterious love interest? Who knows. Sylvia is, also, although she pretends not to be, the mom friend. She's very protective of her friends, (an important reason that of her being an only child -- she likes to think of her friends as siblings she never had) but also particular of them. She prefers to observe them first, then approach them.
She can be aloof, and a bit inconsiderate, and she sometimes thinks of herself as 'superior'.
Sylvia was raised in a pretty normal sort of family -- her father was a wizard, and her mother was a Muggle. They divorced, however -- she got to live with them both, per se, though. No trauma here, no sir.