Re: triathalon bike suggestion
Would agree with the suggestions to get a road bike first.
Ride it, train with it, race a little with it.
If you enjoy the sport, you can then make the decision to purchase a dedicated triathon bike.
Tri bikes are very specialized pieces of gear.
Mine is uncomfortable (compared to a road bike - yes, it's fitted to me and I road 200 miles in aero position one day just for the heck of it), doesn't turn well, doesn't shift smoothly, doesn't climb well, descending hills put my life into jeoprady every time, and doesn't stop well.
But it's fast on the flats and in races, and it was worth the stupid amount of money that I paid for it......to me!!!
By the way, cyclists are famous for their attention to "bike fashion" - brands, this set of components versus that set, etc.
Agree with all the comments that a proper bicycle fitting is more important than the actual bicycle itself.
Think about going to a professional bike fitter and spending the $100-$250 to get your bicycle properly fitted.
Eight hundred to a thousand dollars will probably get you all the bicycle you'll need to learn about the sport.