Even though I work for SolidWorks, I would strongly suggest using the CAD software your mentor uses or your outside machine shop uses. These good people give of their time or give you a discount on their services. You want to make it easiest for them to help you.
As a mechanical engineer, I have used at least 10 CAD products over 25 years, these are software tools. Learn as many as you can.
I hope you make the decision to learn SolidWorks, we sponsor any FIRST team that comes to us,
www.SolidWorks.com/SponsoredDesignContest
Our first goal is to help young engineers get a job in the engineering design field. That is why we will give any FIRST team member the ability to take our first level certification exam, CSWA. At SolidWorks, we believe by increasing your engineering design skill sets, reading a drawing, creating accurate parts and proving your visualization techniques will assist our commericial customers in hiring qualified graduates. Even if you learn another CAD system, these skills are classic in the industry and will not change.
Good luck. Marie