If I am already in the national guard but I choose to do rotc, when I leave college, will I become an active duty soldier?

The majority of active Army officers come from ROTC. This does not mean it is a requirement. If you are in the Guard and serving as an SMP, you will be discharged from the Guard upon receiving your commission. For your commission, you can REQUEST to serve in the reserves (Reserve or Guard) or on active duty. Active duty requirements will be filled first. If there are enough officers to fill the active duty spots, you will receive your request.

For the last few years, the Army has been decreasing in size. This means that everyone requesting reserve duty and some that wanted active are being placed into the Reserves or Guard. The Guard and Reserves are always short on junior officers, so there is a push to fill those positions from ROTC whenever possible.

You go based on your OML. It is based on GPA, PT and other ROTC activities. It usually hovers around 50%. 50% are eligible to go Active duty. It's always based on the needs of the Army though.

You can request a commission in the Guard or Reserves, but the majority go on AD. It is based on the needs of the Army

If the military pays for your college, you have to pay them back with a few years of active duty. If you don't want to go active duty after graduation, then don't do ROTC.

You can request a Reserve commission. They do not have to grant it.

They are not going to give you an ROTC schlorship and then let you stay enlisted. The "O" stands for "officer" and that is what they are training you for. If you want to stay enlisted stay away FROM ROTC.