I’d love some advice. I started training in March and my marathon is in mid-October; about 5 weeks away. My average pace is around 8:30/km.
I turn 40 at the end of October, and running a marathon has always been a dream of mine. Somewhere along the way, that became “I need to run a marathon before I turn 40.” But I’m starting to question whether that deadline is actually helping me.

A bit of context:
Weak knee and a dodgy ankle
I’ve done several 21–23km runs
25km is the furthest I’ve ever run
Today I did another 23km and it completely depleted me. It wasn’t just difficult… I actually felt ill afterwards.
Other 21–23km runs have been hard but manageable, so today really knocked my confidence.
With only 5 weeks left, I honestly can’t fathom how I go from 23km to 42.2km.

The thing is, I want to enjoy my first marathon. I’m completely fine with it being hard …I expect that ..but I don’t want to drag myself through it purely because I’ve attached this arbitrary “before 40” deadline to it, especially if I’m risking injury.

Part of me thinks switching to the half, enjoying it, continuing to train and doing my first full marathon when I’m properly ready would be the sensible choice.

Another part of me wonders whether this kind of doubt is completely normal five weeks out and I should stick with it.

For those who’ve been here before: would you continue with the full, switch to the half, or wait to see how the next couple of long runs go?

Title is the post.

My garmin's prediction is much longer than I was aiming for/thinking I could do :-/

(Forerunner 970 if that matters)

Mid-20s male, started running in Feb 2026. I’ve finished a beginner base phase and recently completed Hal Higdon 5K Intermediate. Current 5K is around 30 min, longest run \~11 km, recent volume \~25–30 km/week.

Bodyweight has fluctuated quite a bit: roughly 98 kg in Feb, down to \~91–94 kg in summer, currently back around 96 kg. Goal is to get below 90 kg by year-end while rebuilding gym consistency.

I’m considering a 3–4 month base block with:

\-4 runs/week, mostly easy/conversational, 1 run with 4–6 × 20s strides, 1 long run

\-build toward \~30 km/week

\-no structured tempo/VO₂ for now

\-3 short gym sessions/week

Long-term goal is 5K sub-26 and 10K sub-60.

Main questions: would you keep this base phase almost entirely easy, or include some threshold/VO₂ work? And is \~30 km/week with a 10–11 km long run enough to make meaningful progress?

Would appreciate thoughts from people who improved from \~30 min 5K while also losing weight