Help..

So my son is 6months an 10 days old. He still has no interest in rolling over. He has no interest in even learning to crawl. He cpuld sit without help for like 5 seconds. Everyone in my family keeps making me feel like a bad mom bc he hasnt done any of that an are tellimg me hes gonna be a delay baby.. Its really starting to get to me bc I do try an get him to roll or crawl an he just refuses..