Why are people considering being bad at math a development disorder? People are good at some things and people are bad at some things. Deal with it and learn to overcome it. In my opinion, you're just being a hypochondriac about this.
Because there's a general level where most people should be capable (provided they've had a basic education) in regards to their abilities to read/write/perform maths.
In the cirucmstance of Dyscalculia it goes beyond just making a few mistakes, or finding it difficult to understand some more complex concepts. It's a struggle to understand even the most basic of concepts, like multiplication or basic algebra, or percentages and the like.
It's when you're at the point that you can't do the regular maths that people are expected to be able to do in regular daily life (like add up the cost of their items on a shopping trip, or work out the percentage for a tip, or understand distances/speeds).
There's a lot of disbelief in things like Dyscalculia and Dysgraphia (inability/great difficulty in writing/drawing), because they're not common and most people don't mention them.
But if you look back about 30-50 years ago (or even more recently), even Dyslexia wasn't particularly believed to exist. Children in schools struggling were just considered lazy or to be an imbecile.
Children wouldn't come forth about being bad at reading/spelling because they thought it was just because they were stupid, and there was nothing that could be done for them.
It's the same thing with Dyscalculia/Dysgraphia. If they can be identified (and they have plenty of symptoms, besides just being bad at maths/writing or reading/spelling for Dyslexics), then proper support can be provided to help them achieve the standard most people are expected to get.
Go and see your school counsellor/nurse/psychologist (if your school has one), and explain it to them.
Try not to start off by saying "I think I have Dyscalculia", because that may look like you've searched it up and want to use it as an excuse for being bad at maths.
But just see if you can get some tests done to prove whether or not you've got it.
