I agree with the other guys Darren. Use some putty and fill in the gaps. I like to mask off both sides of the joint with tape before I apply the putty, then I remove the tape right away before the putty sets. Masking limits how much sanding and clean up I have to do later. I wet sand once the putty is completely dry (I often leave the putty to cure more than 24 hours).

I wouldn't sweat messing up the kit, every modeller makes a boat load of mistakes - it's how I learn. Most of the time, a goof-up is easily fixed. You've just got to be patient. Good luck & looking forward to your next update.

Jason