Train for now or train for later?

I've been an off and on eve player for a little over a year. I'm at 3M skill points with over half invested in mining and reprocessing. Now I want to switch up and get into FW and PvP.

I've run a few sites and made a few thousand LP, but my ship and fits are shit.

Currently I'm running a terrible Atron fit. I've looked at fitting a Tristan with drones since I put a decent bit into drones while a miner. Any ship I want to jump into will be less than mastery 1.

I assume the correct way to skill train is to skill queue everything for mastery on a certain ship. So what I want to know is should I train for mastery on frigates? Or should I train for destroyers since that's the next logical step? Will mastery on frigates be a step on the path to mastery for destroyers?