...in beginners mode ....
Not quite sure what you are asking.
Are you asking if a beginner should learn to fly on a 3 channel, (throttle, elevator & rudder) and not on a 4 channel (TER + aileron)
Or are you asking: Will you have aileron control in the beginner mode on something like a SAFE enabled receiver?
Answer Yes, in SAFE beginner mode you will have aileron control.
Regarding 3 or 4 channel plane for a beginner. This is an area of debate among the hobby. A lot of people will recommend a 3 channel for a beginner. Myself and many others, learned on a 4 channel and got along just fine. I'm not sure 3 or 4 channel makes a huge difference.
I would fly the plane you have.