If you miss out or do not understand early math courses, you are very unlikely to catch up. The above is unlike many other subjects. Flunk an early course in ancient history due to immaturity or failure to pay attention & it will not keep you from passing a later course in European or American history. similarly for various other disciplines. Flunk an early mathematics course & you will probably flunk or have serious problems with later math courses. Learning mathematics is a bit like building a pyramid or a house. Mess up the bottom layer or foundation & the building will probably collapse or be at best be an unreliable structure. Many intelligent folks fail to pay attention to early courses & never learn much beyond early algebra & perhaps never cope with early algebra at a level consistent with their overall intelligence. If you are capable of paying attention & are smarter than a high grade moron, you can learn mathematics thru at least the second year of college mathematics, assuming that you pay attention to the early courses.