cannot open Mcpe after update

my Mcpe on my iPad updated yesterday automatically and I got up the next day and tried to open Mcpe. But every time I did it kept crashing after Mojang symbol was shown. I play on a very old iPad. After this happening multiple times I deleted all apps except for minecraft but it still kept crashing. Please find a solution to this other than uninstalling Mcpe as Ive worked very hard on my minecraft worlds for months and would be devastated to loose them especially my survival world which I play on everyday with my friends.