Delbert,
Only YOU can decide when you are ready for a second plane. My second plane was a 60 size Spitfire. My first take off was a bit premature and wobbly, but I knew to get the nose down, build speed and fly the plane. After that I have had no issues. Each aircraft is different and you need to have an idea as to how it will fly. This is where a flight sim is really handy to have and practice on. Good luck and Happy Landings.