You're still in time and no worries, RL always comes first.
Couple of things you need besides backstory:
-Check how your character performs against the fire giant, 6 trolls, young adult blue dragon, pair of mindflayers, evil 10th level cleric with lots of skeletons, lots of shadows, bebilith, vrock (notice it has at-will mirror image and telekinesis to kite from 880 feet away by throwing random stuff). You need to be able to beat at least 4 of those battles. But if you double the enemy numbers and can beat over half of them, then you're too strong and need to cut something.
-Decide which team to join. Team Bonnie has 3 "ex-villain/antihero" vampires and a sinful angel all going for offense, team Mexilhoeira are basically a mercenary group with an awakened giant crab tank, a chain devil tank, a firbolg utility/support, a robot combat maid with both utility and offense and another vampire. The second party already has 5 people but I guess a group of 4 and another of 6 wouldn't be too much of a problem. Or maybe you'll rather go with the party that has more food vampires already in which case both end with 5 players.
Also I notice a ring of the darkhidden in your character sheet, that's probably a bit too cheesy as it basically makes you perma-invisible in a lot of situations against a lot of monsters.
