In truth, I wished that Edith could find someone close to her age but we are talking here 1919 ight at the end of the Great War when the majority of 'suitable' men have being killed or completely destroyed (eg, psychologically, physically, emotionally,etc) while I recognise that Sir Anthony may not be the same man, I don't think he is too changed and I'm sure that if he were to marry Edith she could help him to find happiness together with her love, care and patience. Besides both of them have common interests and they both find each other interesting (at least that was the impression I got from season 1)
I think it is silly to complain the age gap here because back then it was quite common and there is also Anna+Bates