First of all, it seems you addressed the questions asked of you and after reading your essay I certainly believed this was your goal and passion in life. That being said, I never had to write an essay to get into school so I'm just going to point out some specific grammatical errors and maybe not all of them. I would suggest trying one of the grammar
checking sites for something so important. I've seen commercials for grammerly.com and there may be others. Just a thought.
On to the specifics. Second line – you need a "d" added to determine = determined.
Third line down "a go" needs to be "ago"
Fourth line down I believe it should be "sister and me" not "sister and I". Basically if you read the line through it needs to sound correct for both "sister" and "me" if you were using them individually. (hope I made that clear).
Generally job titles are not capitalized so Registered Nurse should be registered nurse. You should confirm that however.
The line containing "San Diego Master's Entry program in Nursing" is incorrect. Masters should not be possessive. San Diego's would be but I would put the entire school name. Is it San Diego University's Masters… Also frankly that program sounds incorrect. Confirm the formal name of the school and the program. Only put an apostrophe on the name of the school. I don't know if this should all be capitalized either but it's probably OK since you are naming a specific program. Definitely San Diego and University would be capitalized of course.
Second paragraph, change the semi-colon for a comma after furthermore. Also after therefore. Words like these such as "therefore", So, however, etc. need commas, not semi-colons.
Fourth paragraph down, you call SD a Changemaker campus. This should not be capitalized. Also since I don't know what it means they may not either. You might want to clarify that point a little more.
Somewhere (lost where) you say Register nurse. You need to add the "ed," so it's registered nurse.
Lastly, you go between calling the school University of San Diego and San Diego University. I recommend finding the exact name of the school and using it. You wouldn't apply to a job and modify the name of the company. And strangely, there literally could be a university of San Diego and a San Diego University and they might be different schools. I've seen it in other cities.
In general I liked what you had to say in your essay and maybe that is really all that matters. I did find some sentences ran on a bit too so again, I would suggest maybe having an English tutor help you (maybe free at your school?) or using a site. Only because this is so important.
Best of luck to you!