u/Icy-Examination-2748

Hi,
I have been lurking here for months and now need to set my goal for my first marathon in Edinburgh.
50yo male here, training since 9 months, going from couch to 26 miles basically.
Last month I ran a 1h48m half marathon, training volume peaked at 60 miles / week. Longest runs (3 of them) - 18 to 20 miles.
Do you think sneaking under 4 hours is realistic or should I stay with my initial target of sub 5h?
Any hints for the first one?