Pretty sure it’s most likely to be a couple of years at least 2 because you need to practice everytime you’ve got.

Well, the best option for you is to keep practicing with your cousins, but you need to be serious about it. If you practice a lot, you could be fluent in a couple more years. Of course, that depends how good your Spanish is now. Two years of high school doesn’t really say anything: it could be awesome, it could be a joke.

If you take all four years of high school, and then go live in Spain or any other Spanish language country, then…five years.

Actual times may vary.

It’s really difficult to determine something like this…how much you use your cousins as a resource, how good the quality of your time spent, how much time you ACTUALLY spend (as opposed to your plans), all figure in, as well as your ability to absorb the information from the sources you use.

Different people learn in different ways, and if your class or this pimsleur (not familiar with that) is contrary to the best way for you to learn, that will slow you down. Finding the best way for YOU will be the best determiner for a shorter set of lessons.

maybe a year or less if you got all that. buena suerte!