Adding an extra bridesmaid after Covid

Hi everyone



I really need some advice! We have had to postpone our wedding from July 2020 to Sept 2021 due to Covid. We got engaged in Aug 2018 and I asked my 3 bridesmaids pretty much straight away. My brothers wife is my maid of honour we are so so close shes like a sister to me, I also asked one of my bestfriends I met at University I was a bridemaid at her wedding and I'm also a godmother to her little boy and the other bridesmaid is my Fiance's sister we get on so well and shes really important to my Fiance. I wanted to keep it at 3 initially to keep the costs down as I have paid for bridesmaid dresses/hair/make up etc. It has been weighing on my mind pretty much since I asked my bridesmaids that I should have asked my other best friend from Uni as well. We are extremely close but lost touch after uni for a couple of years as she lives in London. Since we got engaged we have became really close again and talk all the time and always make the effort to see other. I really feel like I will regret not asking her to be my bridemaid but really worry that she will be offended that I didnt ask her when I asked everyone else. Covid has put things into perspective and makes me realise how important she is to me and how much I would love her to be a bridemaid.
I just worry she will be upset or think that I'm only asking her now because things have been postponed I dont want her to think she is an after thought. I don't know how to word it to her or how to even ask her? She is coming up this weekend with her boyfriend so I thought it would be a good opportunity to ask her then? Also means I need to get new dresses because they have all sold out and I can't get another one for her ?
How do you think I should go about it? Or do you think I've missed my chance and it will look bad?
Thank you!