I'm going on 64 and ride with a group of 30 somethings while they do their sometimes very difficult interval training sessions.
I find that I can do many of the intervals while drafting, and in parallel with the strong girls at about 21.5 mph but I have to draft the 30+ boys during their extended 23+ mph intervals.
They all ride tri bikes and I'm on a 18 lb carbon road bike. I get into the drops, but will a tri bike help me? I know that a tri bike will probably be more hefty, but can the layout make up the difference?