Hello! My 11 mo old moves forward in a sidesitting position. He doesn’t slide on his bottom, but more on his inner leg. His butt goes up and down with every movement. He usually leans on both hands, sometimes only one hand if he is holding a toy in the other hand. He does 4-point-crawling when there is not enough space for the sidesitting position or when he goes over an obstacle. He started pulling to stand as well. Should I be concerned that I do only rarely see 4-point-crawling? Thanks in advance.