I definitely don't think so. Alot of people dont actually start studying till after xmas anyways. I don't think it will be easy but if you could get through the notes before the end of Jan that still gives you ages before the exam. If you think about it, starting to study now is like the equivalent of starting to study mid june for the summer session - most of the students I know only get going in July once the results are out. Go for it I say
To start late or not? I'd say it depends on your entire circumstances. Are you planning to sit anything else with it? If so, unless you have already finished the other course I'd say don't start ST1 now - its practically Feb!. What happened to your plans made earlier? Are there any implications from your employers perspective of changing track? If you are simply dis-illusioned with your current lot, it could end up being 'out of the frying pan & into the fire'. Your call at the end of the day. Good luck!