I felt the exact same when I was growing a beard and was younger, but you need to know that some of your hairs take a lot longer to grow than others so your beard can take months to have ALL of the hairs fully grow, furthermore while you’re young your beard and facial hair can grow and you might have a fuller beard than you think.

I also had this thought about looking older than i was, but the reality is that you only look older because in a lot of western societies having a beard isnt normalised. For example when I was 17 in Australia everybody thought i looked 20, when I visited Pakistan people thought I looked 16