When looking at entering into this business part-time and not ever having experience, I believe there are a couple different options, which have different pros/cons. The options would be getting training through a captive platform or an independent platform. An example of a captive platform would be a Merrill Lynch or Edward Jones.
Option 1: Captive
Going down this type of track the "pros" would be the great training on the industry and types of different investment strategies offered. The "con" to this is you will be drinking from the Merrill Lynch and Edward Jones Kool-Aid. They will train you to think their way is the only way. You will find yourself in a box and not being honestly exposed to the investment world and this limitation can hurt you long-term.
Option 2: Independent
The independent route "pro" is that you will be viewing the investment universe with an unbiased thinking, not so focused on selling a particular platform. You can learn and understand how all products works, so that you can determine what is best for your client. The "con" is you may find someone who is a salesperson and not a true advisor to help mentor you. Finding an advisor or a salesperson is not the easiest thing to come by. You will need to find someone who is extremely knowledge and willing to help.
Conclusion:
If I were starting over in this industry with the knowledge that I have today I would choose "Option 2" and find an RIA (registered investment advisor) that was willing to train me. They would be independent and be working with a large custodian for their execution. I would also want there to be multiple partners in the firm, so that I was not just learning from one person. I would go and get my Series 65 and life license and start to grow my own book of business.
I hope this helps in providing direction and know that it is never too late to start a new venture. Investors need more help today than ever and this industry needs more ethical advisors helping them reach their goals.