you first chatted in April , he came in June to see you for 8 days, when did he propose to you ?
did you not supply photos of you both together ? other evidence such as emails, chat logs, letters, receipts for plane, hotel etc ?

the age difference should not come into it.

Applicants/Sponsors with a large difference in ages The rules do not state that the applicant and sponsor must be within a certain age differential, but if there is a disproportionate age difference (for example, more than 25 - 30 years), additional care needs to be taken.