Plastic Model!

I was happy that I could make it good well!

***

よくできました！

気を付けて下さい：

WELL　ー＞　よく

GOOD　ー＞　良い

The/My Plastic Model

I got a unique plastic model from my friend--it's a rabbit. It has been a rather long time since I last built one, so it took me more than three hours to make it. Afterwards, when I showed it to my friend, he was very surprised at how well I had done.  
I was happy that I could still do it so well!*

Hi Atsushi. Good job! As to your composition, whatever changes I made were merely done to allow your sentences to sound more natural to my native ears.  I hope that this helps you. J.

*As presently written, everything is in the past tense, which is fine. It would have also been acceptable to have written your last sentence in the present tense: I am happy that …. Given that we, as the reader, have no idea as to the passage of time between when your friend complimented you and your feelings of happiness, it is a bit unclear. Using “was” denotes that you were feeling happy after hearing what your friend said, but that such a feeling has already passed. Using “am” indicates that that it happened in the past, but still has an effect upon you now (as you were writing your post …). It’s a subtle difference, and both are acceptable, it just depends on what idea you are trying to convey. I hope that this helps you. J.