[senna95]

Which would be the best thing for my 14 year old son to begin learning?
I use Solidworks at my job but the school is part of PLTW which uses Autocad Inventor. I dont want him to get used to Solidworks and then have have a hard time in school with Autocad. Any thoughts?

[giz]

Teach him both

[DareBee]

All MCad is similar enough to not cause a problem.
I have had students in that have been trained in SolidEdge and ones that have been trained in Inventor. Either way they were using SolidWorks efficiently with very little effort.
I believe SolidWorks has market share in the field.

[Aquatic]

If you were in Australia

AutoCad because of market share and jobs available!

[mcphill]

I agree with DareBee - the best answer is "Both", and "More is better", and "Either is better than none". You won't go wrong starting him out in either one, and they are similar enough that the skills are transferable. The fundamental education on "how" to model in 3D is the important skillset, not the mechanics of clicking the right button and knowing what menu it is in.