You shouldn't have trouble programming the game if you do the tutorial from top to bottom and don't skip anything.
I personally think it would be a better idea to start with SCI, rather than to start with AGI to get used to stuff and then move to SCI. SCI is quite different. Many people who have made AGI games try to do AGI code in SCI games, and it just doesn't work, kind of confusing them.
For example, AGI does:
move.obj(oA,X,Y,STEPSIZE,fDONEFLAG);
SCI does:
(obj:setMotion(MoveTo X Y RoomScript))
Some people try doing things like:
(obj:setMotion(MoveTo(oA,X,Y,STEPSIZE,fDONEFLAG)))
which obviously won't work. Learning AGI first could lead to confusion. SCI is a fair bit different from AGI.
Also, though more complex, SCI Studio offers far more indepth tutorials and teaches much more step-by-step. Though more complex, it could likely be easier to learn as a result.