I am almost level 28 and i have never done the weekly nightfall or the vault of glass most people that are my level or lower have already done the vault tons of times and the nightfall if i get the dark below will i be able to do it im not bad its just people think im new and dont want to play or they quit half way i have done the vault about ten times and never completed it and the nightfall sheesh thats harder then the vault.. What are your thoughts on this
If you're a completely solo player, depending on your skill, I think you're slightly behind just because they've raises the daily, weekly, and nightfall missions to level 30. Ideally, you'd want to be the same level as these missions to get good items easier. Make some friends to help with weeklies and nightfalls. The Dark below missions are also quite a handful solo.
In regards to raids, you're fine for VoG. I didn't try VoG til I was 28. The enemies at the end are 28 anyways so you'll never be at a disadvantage. I suggest getting to at least 30 before trying Crota's End. If you're having trouble finding good teams, join a clan. Small ones will help you find a regular raiding team so you don't have to depend on random people.
Before the dlc I would have said you will be golden but ow they've moved the goalposts and the nightfalls and heroics are level 30 (on hard) which means skill is pretty much out of the question, you will get destroyed. Immediately. Buying the dlc won't put you at an advantage (unless they choose the dlc strike in which case you can't play it) but your level will I recommend doing some grinding and then buying some vanguard or crucible armour to boost your level, fully kitted out you will hit level 31.