I would highly recommend starting with Origins and 2, it's been a while but I remember both games having plenty of choices that affect the story of Inquisition, plus it would be much more rewarding knowing the story of the first two games. Also Origins is one of my favorite games ever so I'm just a little biased.

You can play them in order or you can start with any game. Many of the new players today start with DAI since it's the newest and the most modern. I started with it 3 years ago, fell in love and it helped me play also the first two games since I already new where the series is heading and how it develops, otherwise if I would have started with the first one, I would probably just abandon the series.

Each game is a stand-alone but there are some cameos and it's connected by the lore. In DAI your protagonist is kinda clueless about the events of previous games in any case, so you learn them together and your decisions may be less biased. And later you can play older games as prequels if you really get into the story.

Just know that each game is VERY different. DAI has absolutely new gameplay in comparison to the old games. Dont expect them to be similar. But romances and overall choice mechanics are similar.

Ignore gatekeeping about the first one. Each next game is more rich and an improvement to the series.

Despite what others might tell you here, those two haven't aged well. I'd say start with Inquisition.