Excellent your trainer was a good choice then and now as well as the engine sounds as though you have everything in hand and doing great.

If you have not run the engine on the airplane and the original fuel tank is still in the airplane you may want to pull it and inspect carefully all manner of bads things can happen in storage and this means internally too. Actually whenever I refurbish an old airframe I make a habit of installing new tanks and usually Hayes tanks also.

On the Decathalon I agree with also with Metalica That is not a good follow on airplane even though it is a high wing. I would generally prefer to see folks go to a good low wing intermediate type airplane. Such as the various Tigers, Nitro planes Low Wing trainer, Keosho Calmato and so on.

It is a resonable purchase though if it has not been hacked up in assembly. So you still may want to do the purchase if you have the will power not to start flying to soon before your skills have had a chance to mature. That always is the problem when folks have great airplanes waiting in the wings to fly that are still over their head. The temptation is hard to deal with.
This is the factor that you see occassionaly when someone recently soloed and going off on his own will loose many airplanes in a row over maybe just days. I call this the 'crash fest syndrome' and its most often due just to impatience in ones personal skills progress.

John