If you want answers then try not to be so conceited, and wait more than a few minutes for people to reply. And since you seem to think you know - then you should share your thoughts on the matter.
We must note that it was never God's original intention to give the priesthood to either Moses or Aaron. It was originally intended that the firstborn son of every family was to be given to God. This changed with the Golden Calph incident. Because the Levites rallied behind Moses at this time, God established that the Levites as a whole would serve him in the place of the firstborn of the rest of the tribes of Israel.
Now, as for why God ended up giving the priesthood to Aaron instead of Moses, the scriptures don't give a reason, though there is enough to offer an educated guess. Namely: Moses refused to go as he was commanded initially, but bickered with God about his stammering and such. His personal fears and worries held him back. As a result, instead of sending Moses alone as his representative, God allowed him to take Aaron along to speak for him. Thus the role that Moses was initially intended to play was divided. Moses spoke to God, performed miracles, and told Aaron what to say. Aaron was the public figure that actually spoke to Pharaoh and the people.
Exodus 7:1 Then the Lord said to Moses, “See, I make you as God to Pharaoh, and your brother Aaron shall be your prophet.
So the priesthood that the Jews ended up with was never the one that was originally intended for them. Their sins grew the divide between them and God so that they ended up with something much different than what they would have had otherwise.