Honestly, it's almost a waste to learn Spanish if you aren;t going to utilize it in your daily life. You're bound to forget almost all of it.
When I move to Panama when I was 10, I started learning as much of the lanuage as I could, and after 5 years, I could carry on a decent conversation in Spanish. I moved back to the States when I was 15, during the 10th grade. I breazed through my first 2 spanish classes in high school, but started having trouble in my 3rd and 4th spanish class (I had only been in the country for about a year in a half when entering spanish 3, the only time I used the language was during those classes). I found that things I remembered being able to speak easily when I lived in Panama were a struggle to remember, etc. Now, after a year of college, I don't know if I could carry on a broken conversation. Anyway, learn it if you're going to use it in your day to day life. If not, it's nothing buy a waste of your time.