I used to do a lot of model rocketry when I was younger, so I think I can give some useful feedback.
I have tried a long-tail design similar to this, and I found it very unstable. My assumption was that the dragging fins would straighten the path, but in practice the rocket waved back-and-forth and turned nearly horizontal by the time the motor quit. I would make the fins shorter and have your rocket body tube at least 10". You are gluing a regular tube between the nose and frame, right? A rocket as short as the one shown will be so unstable it will probable make several loops. This is sort of a dangerous design as shown.
The rocket motor will get very hot. It may bond itself to the frame, and possibly melt the holding tabs. The landing impact may deform the weakened frame around the motor. Using a shorter-burning motor will keep the temperature down.
The forward holding tab is very thin. It could fail, and the motor might just shoot through the top of the rocket. Make a 2mm ring around the top to hold the motor and reinforce the frame.
Expect some of the ejection charge gases to leak out under the body tube and leave powder burns on the frame and nosecone. Seal them with spray paint to make it cleanable.
Your guide tube hole looks too wide. The rocket may be several degrees off from vertical before it even leaves the pad. Again, that is potentially dangerous. Add a guide tube at both the top and bottom of the motor frame, with tighter clearances. They can be short to save material. Consider adding a guide ring to the nose cone as well to keep it straight.
I have not flown a printed rocket because I now live in a densely populated area, but other than the issues I mentioned, I don't think you'll have any problems. It's pretty flexible stuff with some memory to recover from crashes.