Very expressive style. You say that you are only a composer, but I would heavily recommend getting deep into mixing as well. A well-mixed song can take a okay song to great.
In regards to the song, the instrument choices are spot on, especially given that you want to emulate the Age of Empire games. I feel that the track is too mono, so panning for some of the filler instruments (for example the pizzicato strings) can be placed to the side while the main instruments are usually panned center.
The sections flow well from one to the next, but I feel that the piece as a whole is a bit directionless. It is constantly moving from one section to the next without time to develop a motif. At 0:15, the music probably should have built to a rising chorus, but the softer section kind of defuses all the great tension you built in the beginning.
One last point is the volume placement of instruments. This is especially important for melody-competing instruments such as at 0:46, where the oboe and acoustic guitar are at the relative same volume. Choose one or two instruments at the most to lead the song, and have the other instruments either support the lead, or serve as background instruments.
A very impressive piece given that this is pretty much your first foray into game music. I had a listen to your metal albums and it rocks! I noticed some of the faster parts in this current song are reminiscent of some metal music. May fortune shine on your composing path, Cederick!