We run courses every month of the year, if you're willing to travel to the USA.
Are you looking at being primarily a slider up (big wall) jumper?
And you don't plan to jump in the UK?
I'd say probably the 240-ish sizes are going to be a good choice for you. I wouldn't go smaller because the odds are that you will do your first terminal jumps in either Italy or Norway, and landing out in either place you will be very glad for the extra fabric over your head.
But if you are thinking of doing urban jumps in the UK, bigger might serve you better.