We have a saying in hobby rocketry, “Work your way up the alphabet.” It is highly advisable to fly smaller rockets before trying to design, build, and fly an M powered rocket. There are myriad subtleties that can cause serious problems.
As a general rule, if you aren’t sure something is right, don’t risk flying it. Ignoring some detail that isn’t understood or hasn’t been handled has a name. NASA calls it “Go Fever”. The Challenger disaster is but one result. (Proving that even groups with LOTS of experience and numerous smart people can “screw the pooch”.)
Both NAR and Tripoli’s certification programs align with this path as well. Requiring that you start with smaller class motors, and then work your way up to bigger (and some would say) better things.
Contests are a great way to remind us about this general rule. At our club, Northern Colorado Rocketry, we have a very popular “Alphabet” contest. Each entrant starts with an A motor rocket then with a successful flight the contestant moves to a flight with a B motor rocket, and then so on, and so on up through the alphabet. If there is a failure in any flight then they start over at A, again. This contest goes on for the calendar year. The flyer with highest motor class takes the prize, and in the event of a tie, then the total impulse burned is the tiebreaker.
Amateur rocketry is one of the best hobbies to continually learn, grow, and expand your interests. There’s basically no limit to what you can do – Just look at Elon Musk, he’s now talking about going to Mars. I bet he started with an Estes A motor.