Cream is Girl Tails. Her physical capabilities and skills is the same as Tails, her ability to defeat Eggman and keep up with Sonic is the same as Tails. The only reason anyone thinks Cream should stay at home and never say anything about Tails is because Cream is a Girl, and Tails' intelligence often outweighs the entire rest of his character in some people's heads.

Cream being female automatically makes her labelled as a helpless damsel in most people's eyes. They may say "she's a child" but what they mean is "she is a helpless worthless useless female", being six is just an excuse. They don't actually care about that. Hence why they never say anything like that for Charmy, who is also six years old, because Charmy is male. Charmy is a boy, so he is automatically strong and capable and tough.

Tails' whole character is being a kid brother to Sonic, but no, he's "smart" and builds tech stuff, so that means lots of people will dismiss his entire character, motivation, personality and even skill set just to hyperfocus on his intellect alone somehow being all that he is. But that also means they completely ignore his age, pretend he's far older than he actually is, so despite Cream being a mirror of him, they fail to see any comparison.

All because Cream herself is a six year old GIRL, not a six year old "Boy". This is silly. In this franchise, both boys and girls, kids and teenagers, are all capable of doing what Sonic does as long as they have the will to do it. Tails, the "Kid" character, and Amy, the "Girl" character, are both capable of keeping up with Sonic and being heroes in their own rights. So Cream, who is "Kid" and "Girl" simultaneously, should be equally capable. And she has been since her literal debut.