I believed its my fault as Im really confuse on the section "Person you are joining" which I put my son details rather mine.
You should have put your details in "Person you are joining" section instead of your son.
This is a serious mistake, if you have not enrolled your biometrics letter yet, then I would advise you to withdraw the application and reapply again. I believe the fee and IHS will be refunded for this application but I am not 100% sure and will leave this for senior members to comment on this part.
I recently applied for my son's visa in which I put my details in "Person You are Joining" section and in personal details put my son's details.