If you haven't played since T3 then you'll be fine. There's a lot that's changed about the series since then that you haven't experienced. You haven't seen the walled stages, customization, any kind of story/campaign modes, all the gameplay stuff will be brand new to you. If anything you should pick it up because most people have been playing these past few entries. With you it's a different story because the things we're used to you'll be getting extra usage out of it. Overall it's the most hyped Tekken since T5 in 2005. Some people are mostly negative due to how long it's taken to reach consoles but you know how those things go. People comment on the negative things, they rarely comment on the positives. The game comes with over 35 characters day 1, new gameplay mechanics, over 20 stages, Story Mode that even has side character stories, customization, Treasure Battle that's pretty much endless, Arcade Mode is still here, characters have endings (of course), Gallery has every opening/ending from each other Tekken game in case you missed those, gameplay is dope.
Overall if that's what you want then you're good. If your last Tekken was T3 then I'm pretty sure you'll be in a GREAT position. Most of us here were playing the previous eras Tekken so it's just from our pov rather than yours. With you man it's just a completely different story.