the only thing you CAN'T be on the Vault of Glass is under-leveled, because then you just can't do enough damage and die too quickly. As long as you're on level, you can work through it.

If you want it to go MORE smoothly, though, what you need is weapon gear you really like, and it helps to have both subclasses leveled out and at a point where you really know how to use them. I play Titan, so I'll switch between shield and striker depending on the exact encounter, and I have all perks available so I can fully tweek my setup to work how I like. But yeah, first time I tried it I didn't have a sub-weapon I liked that much, then I unlocked a nice shotgun that made it a lot easier after that.

It's doable as long as you're 26+, just know that it is hard and you have to commit a few hours to make progress in it. It also basically requires at least one player that has done it and knows the strategies, or you can try looking online and learning that yourself. Having someone who's done it really pays, though...