As someone who regularly ummed and ahhed over joining WW, or SW or calorie counting on my own, or yada yada yada...
Just go for it
Don't wait, the more you wait the more you will find reasons to put it off, so just go for it
Whats the worst that can happen?
Advice - Definitely the tracking, keep a notebook with you, or a post it note to jot down stuff you might eat on the move. It's easy to have a biccie with a cuppa at a mate's house, and "forget" to add it to your points when you get home.
As with any plan, I would say to give it a good full month to settle in. If you put on one week, so what? Look at the bigger picture, you might have a 1lb gain on the 15th, but over the whole month, you still lost 3.5lbs? just an example. Dont let one blip kick you off plan
WW is good, it doesnt restrict the range of food you can have, I still have my pepperoni pizza once a week, chocolate biccies, and what not... It all fits in!
Good luck!!!!