@anon77664303 You can always lose TL3, no matter if you got it for the 1st time or not. Unless an admin (or moderator) lock you in trust level 3, in this case you will never lose it (actually, an admin/moderator can lock you in a trust level even if you never fullfilled the requirements to have it, as well as lock you in a trust level worse than what you would normally have).
See:
Only admins/moderators can promote someone to TL4, in which case the user will be locked in that trust level (there aren’t requirements to be fullfilled to reach TL4, as it happens for TL1 to TL3, you can only get it by an admin defining you as TL4).