For your first attempt at orchestral it's not too bad of an effort. It sounds a bit heavy on the low end. When it comes to orchestra you balance you EQ with your composition. When you have a lot of low brass and strings dominating the track, it helps to bring in some higher woodwinds to balance out the EQ. Having said that, you do a good job at building up to some great dynamic moments. Orchestra is very fun to write for and I do hope you continue to have fun with it.