Sub 4 NYC Marathon?

Hi all! I’m hoping to run a sub 4 NYC Marathon this year. This will be my first marathon, I currently run a 1:05 10K and a 2:35 half, I Crossfit 2-3 times a week and run twice a week (of course that’ll change soon haha), I’m new to endurance sport and running.

Questions:

1) Do I need a coach to achieve sub 4 on my first marathon? Currently plan to follow the free Nike Run Club Marathon Training plan.

2) Any general advice/ personal anecdotes :)))