That is very good. You need to make sure you use the best flowers you can get - try and avoid defects. It costs a bit but can call a local florist and ask them to pick out some choice blooms for you (one of each of different flowers). Tell them why you want them, and that you want them with as few defects as possible.
It has stacked well. How many shots did you use? Yes, studio flash light will make things easier, and you will get slightly better results - when is your birthday?
It's easy to do, isn't it?