I was a bit confused

At how old Sally was supposed to be? If she was 26 when she got married 'in the 90s' then that would make her at least in her early 40s. I don't think Sheridan Smith looks at all like a 40 year old! She could probably play a 26 year old now!
I know this is a minute detail to pick up on but it bugged me when I was watching!