Great for you for taking this on! I'm a newbie too, and I have a few of my own questions...but from my perspective as a newbie, I would say there's definitely hope! I can now hold the front & side planks (the beginner version!) for 60 seconds. When I first started it was probably only 15 seconds tops. I'm hoping after a few more weeks I can easily do 90 seconds and then move on to the harder version.
I don't know if doing more planks is the right approach? Maybe one of our PBF experts can chime in.