Two Ideas for you:
First, make the underside of the nose smoother! That will help with take-off and landing on grass and increase durability, because it will take much roughther landings.
Second, you could leave the front part as it is now, but make the entire back section including wing and tail sliding in and attatched with BBQ skewers. That way you could easyly change between trainer and delta. But build the trainer first! And reinforce the Joint of the two halves. You could put the servos in the back section and just plug them in/out, but then it is extreamely important to check direction everytime you change.
If it works, this swappebility is going to give you a lot of fun for the start!
Btw, have you looked into simulators yet or had any experiences flying? Even the best plane wont be fun If you cant fly it, so learn, because thats the safest way to the fun!