Thanks so much for your first post and welcome to the Community Forums!
Number ports do usually take around 10 working days from the date that the port request was made. Just to confirm, did you specify when you moved over to Virgin Media that you would like to have your existing BT number ported over?
But yes, please do keep your landline service active with BT until the port has completed so we can ensure that the port does complete successfully.
If you are unsure if the port has been requested, just let us know and we'll be happy to check this for you 🙂
If the form has been filled and opted in for the number port then all should be well :). If you have registered for your My Virgin Media account, you should be able to see the Number Port order from there if you want to take a look. You just need to head over to the 'my account' section and select 'track my order'.
Let us know if you're able to see it. We're here to help