Jack Lalanne On Negativity

"We have so many negative influences out there that are pulling us down. I try to keep all the negative stuff out of my brain because negativity is like a poison, it develops an acid condition in your body." Jack Lalanne.

Negative thoughts prevent you from going for it; they tell you, you can't do this because you're too old, or you have too many commitments or it's all just child's play.
Negative thoughts keep you locked into the safe and familiar.

What you want to do is as worthy as you believe it is. It has nothing to do with other's opinions. Never discount the fact that 'misery loves company.'
Most people who have resigned themselves to playing it safe can't be expected to enthusiastically encourage someone who is doing something  they wish they could do.