Glenn Said:

When I study abroad during high school, how do I get my credit?

We Answered:

With respect to getting credit here in the USA for classes you take while overseas, you'll have to talk to your school counselor. What I can tell you is what our school does -- unless the overseas school is accredited by CITA (forgive me, I forget what that stands for), the classes overseas are treated the same way that home-school classes are treated - they count towards the required credits for gradation but grades and such would not transfer. (If the school IS CITA accredited, everything transfers.) So, for example, if you take (and pass) a semester math class while overseas, you would get 1/2 of a credit applied to the 3 credits needed for graduation. (That's what they are here.) Sorry to be a broken record, but your school is the only one that can tell you what the 'right' answer is for your school.
With respect to the SAT, you can take the regular SAT overseas. According to http://professionals.collegeboard.com/te…
"Last year, over 200,000 students took SAT® Program tests in over 175 countries outside the U.S. The SAT and SAT Subject Tests™ are offered overseas six times a year: in October, November, December, January, May, and June.
International test takers can choose from more than 1,000 international test centers listed online in the Student area of the website. A list of international test centers is also provided in the international edition of the The SAT Codelist, International Edition. Occasionally, supplementary test centers are opened on request where and when necessary. In most countries, students living more than 121 km (75 mi) from the nearest test center can request that we open a test center closer to their home." (Copied and pasted)
Going on exchange is an amazing experience unlike any other! I hope you get to do it.

Irene Said:

How to ask/convince my parents to let me study abroad in high school?

We Answered:

Spain is wonderful, good choice!

Open the conversation by informing them of the educational benefits of studying abroad

Secondly, talk about how it would make you a better person because you will become more open to new things

Thirdly, explain to them how you will learn to speak probably the most important second language in the U.S, Spanish. Add anything else you want.

Close it by telling them how it costs the same as your current tuition.

Good luck!