please help me on my college personal statement?

please help me on my college personal statement?
i will be a senior in high school
but i dont know how to start on my college essay
i am American born Chinese
born in Los Angeles
went to Taiwan at first grade
went back to USA at ninth grade
was a treasurer for a club named Students from Abroad Union for one year
now am the president of that club
gpa is around 3.3
only scored 1740 on the SAT
didnt enroll in any sport season or music class
therefore, i want to work hard on my personal statement
and btw, is it good to write about how my dad had an affair
but he broke up with that woman and has stayed with my mom after all
what shall i write for my intro, body, and conclusion

is it easy to change major in college?
like if i first decide to study stage design
but change to chemistry after it

is it bad to put my major as undecided?

sorry for asking so many questions
but i’m really struggle
thank you (:

First of all, don’t worry about choosing a major right now. Most schools don’t even require you to declare a major until your junior year! Just start out with classes that interest you and go from there. Most incoming freshmen don’t have any idea what they want to major in when they start college, so putting your major as undecided is not a big deal at all.

As far as the statement goes, I would recommend that you do NOT write about your dad’s affair. Instead, focus on your experiences as a child in Taiwan, then moving to the US. You could mention how it has given you the opportunity to grow up with two different cultures and explain how it has made you more accepting of other people or given you a broader view of the world. You could also write about the struggles you might have had when making the transition from being in Taiwan to being in the US, and how you overcame those struggles. Was it hard to make friends? Did you have a tough time with your classes? Did it take a while to get used to the food?

Colleges like to hear about how individuals learn or grow due to a certain event or experience in their lives. Use your unique experiences to your advantage! Write something that is interesting and memorable, because if the admissions officers remember your paper, they are a lot more likely to accept you!