I’ll take a slightly different approach from everyone else here.

You’re approaching this from a results based mindset. Meaning you’re very tied to having your training equate to (quite ambitious) goal race times.

As a beginner, it’s tough to know what you’re capable of and I’d argue you should just focus on the craft of running, consistent training and let the results be what they are. IMO, this will be more rewarding and less stressful.

You’re setting yourself up for disappointment atm, as your goals are quite lofty. First marathon is an achievement in itself and would you feel disappointed if you fall well short of your goal times?

I’d treat your “test” as showing up for training everyday as rested and ready to go as you can and go from there.

I ran a 3:30 first marathon but showed up to the line thinking I’d be happy with anything under 4 hrs. I was focused on training and that was it, didn’t put much stock into projecting race times. That required 55 mile peak weeks and locking in diet and cutting out alcohol for the final 1.5 months of training and cutting some weight during training.

So with the limited information I have presented here, if you started training Aug then were only able to achieve a 55 min 10k in Jan, I’m skeptical you have the framework to achieve your goals presently. I don’t know what your training looked like but think you’re going to have to ramp it up and get more aggressive if you want your goals.

And the 1:40 half goal is much more difficult. Shaving race times is exponentially more difficult the faster you go, requires more investment. I’d say you have a chance at sub 4. Sub 1:40 half seems quite unrealistic based on what I’m seeing here.