My first thought, if you aren't looking to actually close on a home in July 2021, I am not sure that getting preapproval in November makes sense. Often times the pre-approval is good for 60-90 days before they have to pull your credit scores again and have another inquiry. You would be better off, IMHO, waiting until closing the time that you want to close before you start trying to get pre-approval. Timing can be tough, and I know I have been eager to get my pre-approval myself, but there is no reason to do it greater than 3 months out.
Now for the DTI questions, I don't know your actual DTI because 7% utilization on the credit cards doesn't really give me the full picture. I dont know how USDA counts the student loans, some lenders will use 1% of the loan amount others less and some will go with the IBR payment amount. What do you current scores look like? This will impact the rates you get which can change the DTI calculation as well.
If I were you I would focus on getting a bit more of those student loans paid down and getting the car paid off and then trying to get a fatter savings account. As it stands right now, even if you get financing you will be cutting things close just in terms of breathing room. Believe me, I know how eager one can be to get a home, renting can really be a bummer. I too was tempted in the past to try to buy a home when I wasn't really financially in the right spot, so I am not judging at all. What I will say is I am extremely glad that I didn't rush into a home and end up house poor. Even now I have had to stop myself from just going ahead with getting a home and then losing money by paying off my current lease, so I absolutely get you and wish the best with your home buying journey.
