3 and a half year old doesn't want to grow

[fall08baby]

My 3 year old son (he'll be 4 in October) keeps saying that he doesn't want to grow. He says he wants to be small. He also pretends to be a baby.

He is an only child and not around small babies much so I'm not really sure where this is coming from. It's been going on for about six weeks now. The only change in his life has been summer holidays so he is with us all the time now.

This is not a big problem in fact we have just three days ago taken away his nighttime nappy and he's sleeping through the night without accidents.

I guess I'm just curious if anyone has had a similar experience.

Thanks

DS is 2yo and frequently pretends to be a baby. When it first started I realised that I was talking an awful lot about being a 'big boy' when trying to cajole him into doing something new e.g. "You're going to wear pants like a big boy," "You can walk like a big boy" (instead of being carried) etc. Since I stopped doing that he has got a lot better.

Thanks SlightlySuperiorPeasant for your reply. I've been trying to watch what I say to my son about being big, etc. I think you're right this may be what's going on without me realizing.
It is funny though because he is so independent wanting to do everything for himself. I'll just try to watch my words as not to draw attention to what he is doing naturally.
Thanks again for getting me to listen to myself.