There's a lot going on in this image, and although I think you've clearly put a lot of effort into it, it seems like it's too busy to actually show off your skills to any great effect.
The balloons are a cute touch, but they don't really fit alongside the boy, or the birds because there's no real depth of perspective in there. They'd look far better if they were blended in more and resized, I think.
I like the way that you have the boy placed, and the umberella works well in the placement. The addition of what I thought at first was lines indicating movement, does infact appear to be rain? It doesn't sit well with me spread across the image and would have worked far better limited to the boy.
It's clear you have good skills though - and you've sourced (and referenced) the stock well. Sometimes less is more though - and you can always add interest to an image with a texture rather than lots of stock.
I really like the way that the colours have been processed here -- they're almost surreal in their presence.
I'd like to have seen more negative space in the bottom, as I think this would have framed the flowers better and added to the effect, particularly since you've used a rather large font and copyright symbol on the bottom right, which I believe actually spoils the image, sadly.
Perhaps you could experiment with less invasive watermarking or signature methods, and this might bring your flowers even more into the fore, ultimately showcasing the flowers much better.
In summarizing I'd say you've clearly got skills, keep up the good work!