My 7 month old graduated PT and OMT last month and ever since then it seems like he is constantly changing on his milestones. For instance his newest skill is crawling. However, he looks like a frog when he chooses to crawl. He started crawling on Sunday and even though he has not mastered it at all he is trying to pull up on things and if you give him your hand he will try to stand and does well at it. Is this normal?

He does have a 2 year old sister as well if that makes a difference.