I can resonate with a lot of what has already been said on here regards 'unrealistic expectations'. and a lack of realism within the UK education system.
Now, I was born before the advent of Facebook, YouTube, Smartphones, (year 1990),so its slightly different for me, in that I did not want to become a YouTuber. I wanted to be famous, earn lots of money, and had no real realistic plan. I think this was partially because of going to a poor secondary school, with ill-advised careers support, but also I did not attain great grades upon leaving. So I could not go with whatever I wanted; I had to go into something which required lower grades - but still enjoyed - which was Graphic Design.
I kind of had an unrealistic view of the job market at the time, you always think it is easier to find work and you'll graduate University, and life will all be roses afterwards. This couldn't be far from the truth, unless your particularly well connected, already have years of relevant industry exp, or have wealthy parents to rely on.
The most important point is to have a plan B. Always have a 2nd plan and even a 3rd one. Sometimes life doesn't fall in your lap the way you want it too, despite all the effort in the world. Luck is needed to some degree in whatever endeavour you choose (sad but true).
I'm only just beginning to realise what I actually want to be doing at age 28. This is partially down to my own poor choices, bad outcomes, and of course (in equal measure) I am a product of a broken ed system. Pupils / Students / Graduates need to be better informed, and for this to happen the Gov needs to be increasing the budget and spends on reformed education.
I'm in a different place now, than what I was, I have my degree, have graduated, although working in an unrelated field earning practically nothing, but I have a better direction than I did have.
I think more investment needs to happen with retraining people, up to graduate level. So if they graduate more doors are actually opened (not just metaphorically), and people can retrain and be supported by government initiatives, (more fast-track schemes and accelerated learning routes), and more opportunity for people aged 18+ to take GCSEs without having to pay.
I see a failure to get GCSEs (at least 5 A*-C) as a failure of schools and teachers. So therefore it should be free to anybody to have a second go - particularly Eng and Maths. It is very limited the scope to retake, and usually in the hands of lifelong learning and local councils or FE colleges (which often charge!).