Hello sdang003. Welcome to the forum & congrats for being current.
As per the 50-day rule (discussed in details in previous pages of this forum and the 2010 one), you can apply as soon as you # appears in the advanced notification section of the bulletin. It's your choice. Check this spreadsheet to check the decisions of other people in the forum.
For the change of address, I sent them an email and a letter. They replied to the email stating my address was changed on file. Include your name, DOB and CN in the email. If necessary call them.
As F1 student, an affidavit of support might not even be required from you. I didn't send one with my AOS package but will prepare one before my interview. The only guideline out there is that you need to prove you will not be a public charge (again check previous pages in this forum). I don't think IRS tax return forms are a must either. They are used as proof of financial stability. If it's too much hassle to correct your status with IRS & request/fill new forms, i would just send them the employment letter + bank statements, but this is just me.
No guidelines for how many years. Usually last two are included.
Maybe others can help with the other questions.
Thank for the warm welcome reptile. I am trying to hire an attorney for my case. Do you think i need one. How much does an attorney charge. Mine said she wants 1500 and i seriously feel that its too much. And for the address change do you thing, can i just do the AR-11 thing online or do i have to send anything in the physical mail?
Thank you so much for your help.