Good luck with your maiden. The jittters nevery really go away. You can loose some by ensuring a good preflight and that the engine is running well, but when it comes time to open that throttle for the first time......
Get a trusted fellow flier who knows what he's doing to help you with the trims, and to drop a few words of advice when needed. That's one constant I've had for almost all my maidens... someone else out there to keep my head straight. Keep your maiden flight short, too.... just get it trimmed, stall it a couple times high, and ensure that when you do stall test your gear is down. Does no good to stall it clean... I try to keep aerobatics on the maiden to an absolute minimum.... but if the plane is flying well I do like to do a low pass..... Land it hot like forestroke said.... H9 mustang is one forgiving bird but why push your luck on first flight. And above all don't forget this hobby is supposd to be FUN! so enjoy yourself......

Andy