It's your choice, of course, but these days I strongly recommend a year of solitary practice from books before trying to find a group -- your chances of being able to find a worthwhile group go up substantially if you have some background in the work already. If you want to go in for training in a group first, it would be best to do something unrelated to the Golden Dawn tradition -- otherwise you'll have to unlearn much of what you learnt, as the system in The Celtic Golden Dawn has its own distinct way of doing things.