Hello everyone! Can a child without four-legged support first sit down…

Hello everyone! Can a child without four-legged support first sit down? My son started half lying on the stroller lifting his torso while holding onto the stroller (like we do when we lift our press) and trying to sit; when he eats, he usually lies on the hand because he's not lying on the stroller, he's always half lying on our hand, but now he also tries to sit up, lifting his torso and sitting down. He seems like it's too early for him, we're trying to return him to a half-lying position, but he starts getting angry and gets back up, is it harmful?