Why is it that everyone seems to feel awkward and quiet around me?

Hi, I do have Asperger’s which is prob why this happens but I am shit at everything socially and physically. I am not good at sports or dancing or attractive and I am extremely shy and awkward. I keep seeing other people with their parents having smooth conversations but mine I just sit in silence and no one talks. Same with my mates and I feel invisible when someone else joins. Everyone asks if I am ok when I am just unsure how to enter a conversation. Also, I have random bursts where I make people laugh and bring up the energy but then 5-10 minutes later it’s back to being awkward no matter how long I have known them. Also how do I talk to girls without being closed off. I have shown I can be funny but it takes me ages to build up the confidence and I don’t mean by the amount of times I have seen someone, it means that I need an hour or 2 to warm up.