I think a lot of folks plan to train up loads before venturing into online matches, but you'll probably find that there are plenty of players who are beginners or at the same skill level. You might want to create a balance between online play and practice in the beginning as I think you'll find it not only fun, but also that basic FG techniques and a handful of combos can make you pretty competitive especially when the game has just dropped.
So when you first punish someone with something basic, you'll get a feel for the timing to punish and on one of the next outings you may end up extending the same startup into a drive cancel combo or heck HD for that matter

I know this guy who played no tutorials/missions for scII and just pounded online as a beginner and he was in gold league after a month or two. Heh, extreme case - I'll personally be doing plenty of training mode/story mode, but wanna find out who/what's out there at the same time and get a lot of matches, bc online IS the arcade for this version.
(same guy has XIII pre-ordered and he's never played the series - lol!)
You'll also find that losing teaches you heaps, but you may win more than you think...
Dunno man, worthy of thought?