Wrightme43 makes some very good points. On the other side of that coin...
I did modrocs from around 1965-1973. College, cars, and the softer sex, not in that order, interfered.
Started again around 1990. My third rocket after that, my L1, was a 2 or 3" kit with dual 24 mm motors, which I refitted for a 29 mm MMT. Before that my mid-power experience was literally one E15 motor on a 2 or 3" rocket. First L1 attempt (and L2, and L3) was/were successful.
If you are an absolutely-I-understand-what-I'm-doing rocketeer who could likely build a kit with almost no instruction, perhaps you're ready to certify high power. (I have a different skill set from most but am *NOT* brilliant. But rocketry has been my passion for nearly three-fourths of my life.) An L1 or possibly L2 HP rocket isn't all that much different from model rockets, apart from through-the-wall plywood fins and epoxy (not necessarily required) construction. A lot of today's high power flyers didn't have mid-power experience before jumping up.
OTOH if you're not particularly enamored of your modroc skills, some flying with E, F, and G motors is fully warranted. Being conservative in this respect is probably a good thing. Three, four, or nine attempts at certification is less than fun.