Pushing Through the Fear

My son is arbitrary and stubborn.  I wonder where he got that from?
This morning we were having a "discussion" about whether he should join in a school robotics club that uses Lego EVO and teaches about computer programming and such.  Jack went to a week of STEM camp this summer where they built and programmed robots using the EVO system, and he loved it.  But, as I remember, he was also a bit tentative, because he didn't know what it was going to be like.  As the week went on, he loved it more and more, and by the time his team won several awards in the end of week competition and the instructor pulled me aside at the end of the week and made sure to tell me that each elementary school ran their own program during the school year, and that I ought to sign Jack up, I thought for sure he would want to do that!
As it turns out, not so much.  When the flyer came home on Monday, I said, "Hey Jack! It's the robotics club, wanna join?"
"No," he said.
"Why?" I asked.
"Because I don't want to get up earlier than I have to."
"Do they meet before school? It doesn't say anything about when they meet."
"They did last year."
"What time would you have to be there?"
"I don't know."
"Whaddya mean you don't know?"
"I don't know."
"What if it's not that early?"
"I still don't want to."
"Why not?"
"Because I've decided, I don't want to."
"That's not a reason, that's a description of what you want."
And on, and on, and on we go. I began to picture Melville's Bartleby The Scrivener, saying "I prefer not to," over and over again.
I actually threatened to sign him up for the debate team so he can learn what causation means.
At some point, I realized that he was just afraid of something.  He was afraid he was going to sign up for something that was "just too much."  And I realized that he is my son.  He's got introvert batteries, and right now a days worth of school is about all his batteries can manage.  The idea of spending more time there is absolutely repulsive.
I also realized that the reason why I am pushing him to do this is because I regret the fact that I wasn't pushed to do much of anything.  I had the same predilection as Jack, I wanted to get home, to my safe place and just re-charge.  All the stupid interpersonal relationships that school required, for better or worse, just wore me out.
But my school didn't have clubs for things that I loved as much as Jack loved that STEM program.  Or if it did, I willfully ignored them.  See the flyer for the robotics club was given to me by Caitlyn, Jack was hiding his, having already decided that he didn't "want" to participate.
It must be rather annoying to Jack that I understand him better than he understands himself, because when I called him on being afraid, I could see it cracked something open: his pride.
He's not afraid, he's almost eleven, he's not afraid of new things, he just doesn't want to do them.
I began to play nicer, I told him that there are lots of things that I don't "want" to do, some of them for valid reasons, but, in my experience, when my reasons are less than valid, and I end up doing the thing I was trying to wiggle out of, I usually am glad that I did.
"So," I insisted, "you need to have a good reason why you don't want to participate.  If you can't come up with one by the end of the day, you're signing up for robotics club."
As it turns out, he really has no idea what the club does, or when they meet, or what it would be like to be a part of it.  In other words, it's just baseless fear that holds him back.  It's just his introverted nature.
I know he's going to need a push to do this sort of thing.
I needed a push, but in most cases, my parents were too nice to give me that push.
I'm wondering though, where is the line between doing what is best for my son, and letting my own regrets run the show.  I don't want to push him to be what I want him to be, but in this case I have the feeling that he needs the push to be what he actually wants to be and to do something that he will really love.
Unless he comes home with a really good argument, he's going to get a push.
If he does come home with a really good argument, I'm signing him up for the debate club.