Hi I'm new to the site

I have a rescued male cat, Mittens who is 3 years old and just lost a newborn kitten, I had rescued from a parking lot.  We named her Marshmallow and became very attached to her.  We are thinking of adopting a new cat.  My kids want a kitten about 4 months old and I want an adult cat.  I believe an adult cat would get along with Mittens better.  Can anyone give their view on this?  Thanks.

Welcome to TCS!

I think you should focus on the new cats' personality, rather than age. What personality would fit with Mitten's the best? Is Mitten a very playful cat or is he mellow? 

If he's playful, a younger, more playful cat would fit well. same for opposite personality.

Thank you, Draco,  for your response. Since  Mittens is not so playful, long-haired Maine Coon mix,  I guess an older cat would be better.