The TCG is programmed to comply with the Mongoose 2nd Edition Traveller Core Rulebook, with random rolls on all tables. However, that doesn't mean you can't change your character.
Stats, skills, equipment - everything is editable, so if you need to change something to comply with your group's house rules, or you just want to make a few tweaks, go ahead! We understand that having fun is the most important part of tabletop gaming, and nobody wants to be stuck with a character they're not excited about. You're in charge, not the software.