7 month old not doing much...?

So I have a seven month old who all he does is roll around. He isn't close to crawling or sitting up at all and I'm getting worried since two babies I know that are a few days older than him are already sitting up on their own (one of them is a girl and has been sitting up for months, the other is a boy and has been sitting up for weeks). Should I be worried? Or is it just he's learning slower?

Babies are called babies for a reason lol They are very new to the world and do things at different times. Yours sounds fine to me.

Mine will be 8 months on the 20th of this month and he isn't crawling yet either. He moves his legs like he is, so I know here soon he will be. He also isn't sitting up either, he will for a long moment then falls to the side. All babies do things different at different ages, they WILL/DO eventually get there and when they do, all you will be saying is "Put that down. Don't Touch! Watch your head. Stay out of the bathroom!" ...lol  

LO started sitting up at 7-8 months, crawling fully at 10 months. Shes totally normal.

Sometimes I feel like she's soo behind though because we have a friend with a baby a month younger who does stuff before her.