European Citizen, under 21 - I have been waiting for over a month. Is this common?

I applied for Pre-Settled status a day before my dad did (21st August 2019), and I am still waiting. Meanwhile, my father got a reply within 4 days. I did not wait for him to apply first because I have been working and studying in the UK for over 2 years, so I thought that the 4 calendar day waiting period would be accurate.

It says on the Gov.UK website that I may have to wait longer if I am under 21 and have applied without a parent... But why? I have national insurance contributions, my NIN is tied to student finance, so I can't see why they can not just use that as evidence that I have been residing in the UK. I know the system is stretched with all of the news about a no-deal Brexit but why have most European citizens received a reply within a couple of weeks, and I (along with a small percentage of others) have been waiting for more than a month and a half?

I do not know if I should call them again because the first time, they told me that a case worker "may need" to check my application. They are overwhelmed by the number of people applying and can't give an answer as to when my application may get an answer. Still, is there a possibility that it may have been left out of the queue? Because I took the photo with the app at the end of June (don't know why I forgot to finish it) and got my application number on the same day as when I applied. Could have there been a bug? So many things are not clear...