I'm 34. I don't care how deep someone's voice is. I've done VoG with people who sounded like they were 8 years old but played fine and communicated fine. The only time I will drop from a group due to younger players is if they're being obnoxious or irritating. But that has nothing to do with their age, because I'd treat someone in their 20s the same way. Just be respectful, and try not to think of it as "other players helping you do a raid" and more like everyone playing on the same team to achieve the same goal. For what it's worth, it's a little annoying to have someone beg you to help them, as opposed to asking "hey I'm going to run a raid, do you want to run it too?"