u/Better-Let-9594

So I’m 26M and I got into running in January of 2026 after being an athlete in other sports all my life. Did a half marathon in April after training for 3 months for it and finished with a time of 1:35 in a very flat course. I’m doing the marine corps marathon in October and would ideally like to Finnish under 3:30 but I slacked off on my training in June and July. I have not run more than 16 miles in a few months until this coming Saturday. I really do not want to Finnish over 4 hours. Am I screwed?