Being a local will make it easier for you in applying and a 3.8 GPA is very competitive! It’s great to be involved, even try to take leadership positions in any clubs you are in and volunteer! Also, make sure that SAT score is strong.
College is an expensive venture to undertake. There are scholarships and aid available, and living at home while going to college would be a great way to cut back on expense for college (definitely wish I could have for undergrad). I’m not sure what your financial situation is, if someone will be helping you pay for college, if you have a job/how much you have saved, etc.
My advice is this: meet with the admissions office, collect information, and crunch the numbers! You are in the best position to know whether or not YOU can afford it. Here are some stats on the costs of attending as well as Financial Aid. http://arweb.sdsu.edu/es/admissions/costs.html
Furthermore, my advice is if you don’t know what you want to major in/do or if it might be difficult paying for college, go to a community college and knock out the first two years without breaking the bank! SDSU gets a lot of transfers from local community colleges. There is the local transfer admissions guarantee that you might want to look at over here -> http://arweb.sdsu.edu/es/admissions/transfers/
The great thing is that you are thinking about this so early and you have plenty of options! Hopefully this helps, and if you have any more questions or concerns feel free to ask!