You are not ready for the Vault of Glass. The enemies start at 26 and are 28 by the end. Being only 25 means to do over 50% less damage than you should. Any team that takes you will just be carrying you. I recommend waiting til you're at least 27 before you do your first run so you'll actually be useful. Just because you can access an activity doesn't mean you're ready to do it. Save you and your team a lot of frustration and wait til you're properly equipped. Grind the strike or crucible playlist to earn enough rep and marks to buy gear from the tower vendors. Vanguard is the easiest to earn for. Good luck!