Is there always a “designated” person to lead/move the party?

After have played only a few session (actually 5 sessions of 2-4 hours) I’ve noticed something that I found quite strange.
In our group we are 4 players: I (Newbie), A (Experienced), B (Newbie like me), C (Beginner).

This is an optional description of them that you don’t have to read if you don’t want.

  • I‘m always quite quiet, looking for in the situation trying to understand the scenario and the behavior of both NPC and the other PCs (AKA: learning). Also, I always take care of the team, I mean, I always try to do the most wise and less dangerous or self-destructive actions (like ask forgiveness to someone that C tried to persuade with a low roll) – when they give me a chance.
  • A is 100% of the time roleplaying, he is really in his character and play as him character would do. Even when he speak, he speak as if his character would do, his way of play it’s inspiring. Like a good paladin he helps weak NPC, he complete his promises and fight with evil creatures until death (actually he use his body as a shield for us). Also, basically he is the only reason why we are doing the campaign of the DM (he offer him self to protect a lady while we are moving his to another safer location).
  • B is really indecisive (maybe a bit like me, but I don’t start speaking randomly when I don’t know what to do). Sometimes he has some interesting ideas using his druid’s spells but it’s difficult for him explain that ideas. He is the most charismatic person in the group but he almost never talk (and when he do it he has really bad rolls). Also, I am not sure if this is his natural behaviour or if he was depressed by his bad rolls, but in the last session he get drunk (his PC not himself), cast a destructive spell randomly “because of his drunkness” and killed C… he always do roleplaying in the worst situations…
  • C is interesting, great part of time he is wishpering (secret chat) with the DM (I know that because sometimes they forget to use the whisper command) and he do strange but also interesting actions (like try to take a raven and discover actually they were 3 druids, try to steal a horse, get an arrow shot, be killed by B and all of us be kicked and banished from the tavern… all in the same hour, when our actual mission was get some information of a certain person).

Okay, that was our team description. The problem or curious thing I note is that A is always moving or leading the group with his perfect roleplaying, we are the 80% of time following him, while he is talking with an NPC we are just looking around the place, and when he want to do something (kill some harpies or defend a lady) we follow his command, willing (like me), or unwilling (like B).

But, when A isn’t present (2 of the 5 sessions) the session get slower, the DM explain the situation and… we don’t answer, we aren’t sure what to do, our only reason to protect the lady is that A convinced us, he has the plan, not us (also, in the same day he wasn’t present we reach our destination so we wasn’t sure what to do at next). Because no one was doing something and the silence was getting longer I felt the responsibility/obligation of keep moving the session in order to not get stuck, and I tried to do my best, but it was difficult, I don’t use to talk so much and try to give orders to people that are’t willing to obey me or has different opinions.

Luckily, in the first time I managed to move them to a shop place, and the DM used the rest of the session’s time to sell items. But in the second time, I barely move them to a tavern and I get exhausted, they started doing stupid and unproductive things (well, B had an interesting idea, talk to the drunk people in order to gather information, sadly, he also got drunk) while I was trying to get some information, while at the same time NPC weren’t willing to give me that information and they started looking us (with a focus on me) in an uncomfortable way.

My question is: Is it normal that there is always one PC designated to lead the whole party (talk with NPC, gather information, give orders, etc)? Also, in the case that “the leader” isn’t present, How can I (as player) encourage the others PCs to keep moving in the campaign and not get stuck or do unproductive actions?