It doesn't need to be harder because you are older. Many young minds lack developed abstract thinking. I recall hearing that many don't develop this until their

It doesn't need to be harder because you are older. Many young minds lack developed abstract thinking. I recall hearing that many don't develop this until their mid twenties. My first pass in 9th grade of geometry and 11th grade trigonometry were rough. I later self-studied and found the material to be crazy approachable. If you are still struggling, I advise going further back in your studying or getting a good tutor who will help fill holes in your knowledge.