Chaka Quaker

I arrived in the US on April 19, 2014 with a K1 visa, I was 25 years old. My K1 visa status expired on July 19, 2014. I assume, I was out of status until USCIS received my I485 on December 31, 2014, I was 26 years old by then, I say ‘I assume’ because I don’t know how the status changes after the K1 visa expires, and after submitting the I485. I know the K1 visa is an non-immigrant visa, so I was not expected to register for selective service. I know that now, because I’m trying to do N400 and they ask me if I lived here between my 18th and 26th birthday (not including the time I lived under an non-immigrant status). So from July 19th, 2014 to December 31st, 2014 I had no status, which makes me believe I should have registered for the 1 month and 10 days I had before my 26th birthday (my birthday is in September. At this point, I believe I must say I lived here before my 26th birthday even though, I didn’t get my permanent status until Dec. 2015. Because of this, I must present a status information letter from the Selective Service. I’m turning 31 years old in September. I’ve read some posts that say that would be 5 years after failing to register, therefore, this may not be an issue for naturalization in regards with the Good Moral Character. I reach out to you guys because I want to know if it is very likely that my n400 application is denied because of this. I wouldn’t like to invest time and money if this is clearly heading towards a denial. I would also like to know what you guys know about applying after turning 31 years old and whether or not I should answered that I lived here between 18 and 26 years of age even though I was on an non-immigrant visa, then out of status and then successfully adjusted my status after turning 26 years old. Thank you very much for your help. ***Disclaimer***: I’m not trying to comfort myself. No excuses, I should have known better. So I appreciate your help, rather than comments telling me I should know the law.