You will have a fair chance. Majority of the seasoned players rarely ever pops by the lower tiers because there's not much to do or achieve when you've already passed that hump. Plus, there's no real challenge to be had. So no need to worry about being the plaything of experienced players.
As for decent, not sure what qualifies as decent but everything in Tier 1, 2 and 3 can be achieved quite fast without premium or putting in hundreds of hours. That puts you in range of the various T-34 models, Panzer IVs, a good portion of the Shermans and some solid tank destroyers.
Pretty much that all of that. The lower tiers in arcade will have you working out all of the mechanics of the game pretty quickly and you
will die a lot, but so does everyone else
Once you get into Tier three it will start to get a bit more serious and you should be able to move into the sim events or at least RB mode and escape the Arcade madness.
GF is a lot of fun as you can use real world tactics even though about half of the maps get old really fast you will work out what tank to bring to certain maps and certain game modes. Don't spend all of your initial Golden Eagles in the really low tiers like most of us did as we had no idea what the deal was with them also, use boosters as you get them as they run out fairly quickly and you get quite a few.