OP,
There is something important you need to know - you are not the first one to experience what you are feeling and you will not be the last. You are faced with what could possibly be the biggest decision of your life so far, it is normal and expected to question whether the SA path is the right path for you. It is also perfectly acceptable to ask your question, it is best that you have all the information you need to make the decision that is right for. YOU.
The others who have posted already have given you some solid advice. As
@ekb1398 mentioned, you have the first two years to decide if the Coast Guard (not just the Coast Guard Academy) is right for you. I fully endorse his advice - if you decide to attend USCGA, wait until you experience 3/c summer and the REAL Coast Guard before you make a decision. CGA is a pressure cooker, it is not always fun, and there is always a challenge in your way - there are also restrictions that some people struggle to adjust to. Experiencing cadet summers is a perfect way to experience what your life as a Coast Guard officer could be, at least for your first tour after commissioning. My very first academic year roommate made the decision to leave at the end of our 2/c summer before entering our junior year. She was performing well and would have made a great officer, but she ultimately decided the Coast Guard is not for her and is very happy with her life now. There is a reason why the Coast Guard gives you those two years to figure it out - because they expect people to realize that it is not for them. You are 17/18 years old. What you want now may not be what you want later in life, and that is okay.
As others have said, take the time to think through why you are uneasy. Are you nervous of what swab summer will bring? Are you worried about the rigors of academics? Is it unsettling to leave everything you know behind and start anew? Are you afraid that you will struggle to adapt to the military lifestyle? You are NOT alone if the answer to any of those questions was yes!
I'll let you in on a little secret....if you decide to attend USCGA or USMMA, it will NOT be the last time you question your commitment or desire to be at CGA. I questioned mine multiple times over my time there, and have questioned my desire to remain in the Coast Guard more than once.
Now, I agree with the other posts that you absolutely NEED to make sure that your decision to attend a SA is yours alone. Do not let anyone influence you, whether it's your parents/guardians, a coach, a friend, girlfriend/boyfriend, guidance counselor, or even anyone on this forum! You are an adult for all intents and purposes, it is time for you to make an adult decision on your own.
There is one element in
@sanman 's post that I disagree with - do not worry about the person who would be appointed if you declined or whether or not they are 100% committed. That has absolutely no bearing on your decision. It is your appointment that you have earned, not theirs. Yes, I'm sure there are people waiting to hear that are very much committed to the IDEA of attending CGA - but no one KNOWS that they are 100% committed until they begin their four-year experience when they step off the bus on Day One. I thought I was, my classmates thought they were, and I'm sure current cadets like
@ekb1398 thought they were too - I'm even sure your fellow potential classmates think they are but only time will tell. Even AIMsters, CGAS prepsters, self-preps, and prior enlisted cadets will question their commitment as some point.
Take a deep breath, think it through, and ask yourself - on Day One of Swab Summer or Day One of Indoc at USMMA when they tell you to raise your right hand to swear an oath to defend the Constitution of the United States - do you see yourself rising to that challenge?
Best of luck! Feel free to PM me if you feel the need to ask any other questions privately.