FIRST (Furman Institute of Running) Marathon Training: Advice Needed

Have any of the runners on the board tried this marathon training program before? It’s from FIRST (Furman Institute of Running).

I’ll be running my first marathon (Zydeco Mrathon in Lafayette) on 3/14/2021. I got this training plan from my brother in law who runs about 5 times a week.

Little background on my running: I started running in August 2019; could barely run an 8:30 mile without feeling absolutely gassed. I started training, running 3x per week and did my first 10-K (Cajun Cup) in early November. Most of my training runs were in the 7:30-8:00/mi range and I ended up finishing the race with a 7:05/mi pace. After surprising myself, I signed up for a half marathon in March 2020. For this, I ran 3x per week. Tuesdays, I’d run 2-4 miles, Thursdays, I’d run 3-5 miles, and Saturdays, I worked my way up to 12 miles before tapering down before the race. Since I was (and still am) a noob, the midweek runs were done between 6:30-7:30/mi with the long runs anywhere from 7:00-7:45/mi. Completed my first half marathon in 1:34:48, for a 7:14/mi pace.

Since then, I continued to run anywhere from 10-20 miles a week, and over the summer, primarily focused on triathlon training. With my weekly mileage now about 15 miles/week, and with having had good luck with the 3 days per week training, does this training plan seem reasonable for me?

Thanks in advance

ETA: My goal is to finish the marathon between 3:15:00 and 3:30:00, or somewhere between 7:26-8:00/mi