Forgot to sign cover sheet

Hi so I applied to Oxford for history and after looking over my written work today I realise I forgot to sign the cover sheet. This has made me extremely worried that they won’t accept it anymore and I was wondering if anyone else had a similar situation. I have emailed to ask them but it may be too late.
it is a handwritten piece of work and so the handwriting matches my cover sheet and it is signed by my history teacher so I hope that is enough to prove it is mine but I still worry.