No vosszaa, the game will not take your profile online...i started with an offline profile and a notice came up before i started answering the question you asked. You'll need to create a new profile if you want to play online...at least for now.
The reason you can't take your offline profile online is to prevent Cheats/Hackers(yes hackers, got to TDU2 forums if ya don't believe me that hackers are already at work hacking the leaderboard race times ie they have race times like 0:00:01 which is impossible for a 3-4 min race), for using cheats like money cheat so they start the game lvl 1 with 1billion credits, would that be fair to others online that don't cheat.
People can cheat online on this game directly, so offline/online, makes no difference in this regard. TDU1 never offered the ability to change from an offline to online profile, so I didn't expect TDU2 to be any different. You could modify the savefiles though in such a way as to fool the game into thinking it was online. I'd bet a similar thing can be done here, without revealing too much info..