I started into triathlon at 46!

Only you can know if running with bunions will be OK.

My first triathlon was a sprint distance race with a pool swim; I think a pool tri is less intimidating for a first tri than an open water swim (OWS).

As already stated, age groups are usually in 5 year groups but sometimes it will be 10.

The fact that you are already a god swimmer puts you way ahead of most beginners since swimming tends to be the hardest to pick up and the most intimidating.

Welcome to the fun but be warned: it's addictive!