I'm more carthorse than racehorse, certainly not built for hill climbing.
I came into audax from CTC touring not racing. I am not a turbo slave.
In 2014,I didn't do any calendar events. In 2015,I did enough to qualify ,plus one hilly 200, a month before going to Paris. 82 hours.
In 2018, I almost did an SR(no 300) but went mad in 2019 doing 3x600 and loads more. PBP was a blast I but took my time to enjoy it. 84 hours.
Given the current entry rules ,you might get in quite easily with a 400 in the preceeding year.
Don't start fretting yet.