How old are most superhero Sidekicks?

15-16 is about right. Robbins tend to start out young and they all usually last until their teens before they go on their own and become another hero like Nightwing or Red Robbin or have an unfortunate incident like Jason Todd.

Spider-man just had a very short lived side-kick who about 16 or so. He was a high school kid named Alpha.

I think it's typical to have them in their teenage years in order to explain why their a sidekick and not a partner. A young hero usually needs a mentor, where as an older hero would be more mature and typically not need any mentoring.

15-16 seems like a good age to me. I think Robin was like 8 when he joined Batman in the 40's. (Although in the 40's I think most of the sidekicks were very young like 8 or 9 to appeal to the kid readers.)

I think of a character like that performed via Diedrich Bader in workplace area. A blue collar neighbor to the white collar tax-guy who acts as a comedian foil. much less smart, yet greater philosophically attentive to his place interior the international, and who in step with probability has strengths the place a tax-collector would have weaknesses.

They're young enough that it would be unconscionable for an adult to drag them into the dangerous situations that they do.

SuperHeroes dont age, so it doecnt really mattwr.