"Taking a break" and "dropping off" are the same thing. Whether you "drop off" because of "temptation" or "necessity"...either way you quit, and there's not a whole lot of difference...you aren't competing anymore. We all drop off sometime...whether it's because we give in to temptation, face the "real world," find ourselves no longer in the competitive mental state required to compete at that level, face physical breakdown, or die, it's eventually inevitable. The question is when, how far you've gotten, and how your experiences have changed you before you "drop off."
There will be times when cycling will be the same as swimming. There will be times you hate it, times when it "gets to be too much," times you get "bored with it," times when it is not at all fun, and times that you'd rather be doing anything but cycling. Even when you love a sport, with that much training, you will not always enjoy it. Sport doesn't work that way. A good athlete faces these demons and trains anyway...there's never any question whether or not he'll get out the door and get his workout in.
The biggest problem I see with shooting for a goal this soon instead of one farther down the road is the possibility of burning yourself out too soon. As I said, I think you're better off with a longterm goal, just because I think you'd have a better chance. You could work on a base for years, and figure out exactly what works for you. But talk to a coach about it, and they'll give you a better idea of how to train and peak than I can.
I never said you'd drop off in a month...I said you'd have to be willing to sacrifice.
You'll face doubters a million times over throughout your career. I don't consider myself a doubter, but I consider myself a realist. If you find yourself rattled and upset by what I'm telling you, you'll never make it. But if you can read my posts, understand that the road ahead is hard and long, and accept that and forge ahead anyway, you're one step closer to your dream.