Did you write a scene where your Main Character looks in a mirror and notices details of their own appearance, so you could describe them?
The biggest reason that mirror scene is so clearly evidence of a beginning writer is because over-description is also a sign of a beginning writer, and the mirror scene is just an excuse to do it.
It’s quite common for us to be taught in school that we should “use all five senses” and “describe things in detail.” Unfortunately, the teachers that tell us these things aren’t trying to make us better writers; their job is just to make sure we know the grammatical rules and don’t shirk from expressing ourselves on paper. What they taught us is not literary; it’s merely academically correct.
Meet a new person. Talk to them for a minute or two. Now walk away or close your eyes. Ask yourself: How many details do I remember?
Better still: How many of them are actually useful in understanding who this person is?
Certain details — like a look, a tone, a uniform, cleanliness/slovenliness, a pleasant or disgusting odor, wearing a power tie, expensive shoes on a poor character, a tattoo with symbolic meaning, words like “prissy” or “statuesque” or “disheveled” etc etc etc — these are actually important, because they suggest lots of information about this character. But most visual details are not important, and a TYPE DESCRIPTION (even something as simple as “he was a surly cop with arms as thick as your head”) are actually much more evocative.
Readers have their own imaginations, and visual details are usually more effective when used as associative triggers, rather than simply a list of empirical facts.
Things like hair color, eye color, color or brand names of clothing, pattern of fabric… this stuff is almost never important, and it simply produces cognitive overhead the reader must process without reward.
Just stop it.