Yes, and Yes... You can file 90 days in advance. Do not leave blank spaces...For eg. If you don't have middle name, say NA, same with Spouses/Children info.....My friend did the same under almost every blank fields.....I think the N-400 Booklet says to put in NA as well. Use the PDF form on the www.uscis.gov website. You can save it and update the information later as well. Good luck to you, and Congrats !