Are hobbies in the CV detrimental?
It is part of your experience, so should go in. It also shows, to a degree, that there's more to your life than just science, making you appear more rounded. It also explains the age discrepancy. 

However, should the place you're applying for require a nerd, who would appear totally immersed in the task in hand,  it may be considered that you have a somewhat butterfly approach - trying out something, but not following it through.

Some thought will be needed considering the c.v., and be more mindful of the recipients of it. Thus tailor it to the exact post applied for: tell them what they need to know. Or what you think they need to know...