For a first piece it's quite good. Banner flows well. My big issue is the fact that the focal is too blended in. Far less green on top and you should be good to go. Text could be a little more noticable, but it's not really a problem. Colorscheme was thought out fairly well, points for that. A border would be nice as well.
Overall, good work for a first attempt.
Overall, good work for a first attempt.