Keep it up! I’ve got 9 under my belt. The first one is always the hardest to break though the mental and physical barriers! Pace yourself as the halfway point of the marathon is actually mile 20 once your body starts to eat your muscles for energy.
I was always big on gels and Gatorade endurance formula back in the day. I’m retired from the marathon distance now but ran a 2:27 back in my prime. If you’ve got questions shoot em my way, I’d be glad to help.