In reply to Kmo86:
The two things that precipitated the biggest number of (successful) adventures in the history of human endeavour are:
- people being told that they couldn't do something
- after many drinks in pub getting challenged, then not being able to back down the next morning
The combination of 1. and 2. virtually guarantees "death or glory". Since you have been primed by the first one of these magical factors, your chances are high - if you are a stubborn person I can guarantee it ! (although not yet which I am guaranteeing out of death / glory. Hmmm.. where is my magic 8 ball again?)
Don't know if walking poles will help you or just be a nuisance, but there's one way to find out.
B*ll*cks to the swimming, you are posting here because you want to walk the 3 peaks, don't settle for second best. Find a good walking companion, get the miles in your legs, this takes time to accumulate, like regular walking over a period of time and yes... eat when out on the hills!!!! not only chocolate bars mid walk, but real solid calorie rich gut-luggage when you are out on the hills a solid cooked breakfast (veggie or meaty, up to you) before you set off will help greatly.
Find a walking partner, start getting miles into your legs, you don't need all the latest fancy kit as long as it is sensible/appropriate clothing so don't think you need to waste money. Start accumulating those miles into your legs and build up the distance slowly over regular walking
GO FOR IT!