This reminds me when I was a sprout back in ARR and at that time I was doing msq enjoying the world, I choose pld for my first class and since this was my first mmo, I had no idea about the class systems until in some dungeons some people tought me how to move as a tank XD (in my mind I thought that those instances were like any other online game with no class system).
Then I faced my first wall, the first garuda in ARR, that party asked me in chat if I saw a video or a guide and I was like "no, totally blind (I was doing everything blind -still doing this though on msq xD)" and then one of them explain me in chat what I needed to do, that was something new for me that I need to study for a fight, I tried to do what they explained but probably I didn't understand very well (as my first language is not english). The duty was dissolved and then I was afraid of doing that again.... but I needed to do it in order to advance in the msq...
Back in that day I was on an ffxiv online community in google+ I explained my experience with Garuda and that people gave some advice that has to do with my lvl or ilvl and where to gear up and they cheer me to try again, so I did what they told me and also I saw a video on youtube about that fight and then I tried again, everything went so well and I felt awesome also in party chat one of them told me "thank you for not being a shitty tank" that comment was also so good read but that person didn't know that in my first run I was a shitty tank xD.

And nowadays I have done savage and ultimates (just missing TOP) so everyone can improve over time you just need the courage to do it.