To answer your question right away, yes, you could definitely watch the Progressive movie right away. It doesn't reference anything that wasn't already shown in the Aincrad arc.
However, before you hop into it, I do want to mention that the movie is more like it's own separate thing. It's not worth trying to figure out how it connects to the rest of the story (for the things that don't make sense to how they connect to the main story) since even Reki mentioned that he has no plans of adding stuff from the progressive movie that are anime only into the main novels.
The movie doesn't follow the first Progressive arc almost at all, but I still say that it's a pretty good adaptation from a series standpoint (They actually got a director who knew what they were doing with the series for once!). My favorite character was basically cut and the entire main plot from the novel was cut too. It sounds odd, but it still works as it's own thing. Especially since Reki had more control over these anime only parts compared to other stuff that I won't mention due to spoilers for Tat.
Anyway, I do know exactly who you're talking about Kat. I've honestly haven't seen that creator make a proper point about the series. There's entire videos that people have made entirely debunking almost everything they've said about the series.
I still don't like how they're doing the dub for this arc, I'm actually liking it a lot less than what I originally did, but I'm also seeing how the anime adapted the novels much worse for this arc than I remembered.
You'll probably see what I mean by that Kat. I feel like many of the emotional beats don't work as well in the anime like they do in the novels. The way they skip a lot of internal monologue cuts entire aspects of the characters, especially Sinon.
It makes it feel more superficial to me.
The dub really doesn't make it better.
But at this point i'm just doing my usual complaining.
Something that the anime really doesn't do a good job conveying is how Kirito properly dodged the bullets in the Untouchable! mini-game. The novels properly state that most mobs and NPC made in the Seed aim by turning their eyes to where they will aim (For mobs and NPC's that have regular eyes). The gunslinger NPC was doing the same so it was easier to predict where the bullets were going at all times.
The anime just kind of leaves it to "he's fast" instead of mentioning the eye detail.
The one thing I do like about how the anime is formatted is that it makes it so we've actually met Death Gun before. They did cut plenty of Death Gun's lines that would've helped to figure it out, but they did pan over to the character for a bit.
I doubt most people remember them though.
The novel doesn't have that part of the story until volume 8 while the reveal of who they are happens in volume 6.
As for why Kirito reveled himself right there and then, do remember that his people skills aren't the best...he did consider other options though.