Ok I know I am probably worrying about nothing but going to ask anyway because it's hard not to worry 
Baby is nearly 10 months. Earlier I put a new outfit on her in 9-12 months size. There was a headband that came with it and it's WAY too big for her. Rest of the outfit fits ok, although slightly loose.
She is very alert and active, crawled before 7 months, pulling up and standing on her own for a few seconds, very vocal, pointing at things etc. So seems normal developmentally but we missed the last check around 8 months because of lockdown.
So I know it's probably nothing but just worried her head isn't growing as it should be? They measured at last check we had which was 12 weeks and it was all fine.