Please I need your help and advice

Hello, Dear Macbook Forum Members, recently I bought a used Macbook Pro 15 (late 2010) from one local shop which was selling used and kind of fixed laptops, I could afford only this option because Macbooks are pretty expensive and not everyone can afford it.

And I'm new with Mac iOS. Still learning it.

So, my problem which I need your advice is when I bought Macbook it had admin account. The seller at the shop told me the password of the "admin" account and I started to use it. I downloaded my photos with my family and my friends to the folder and then dropped photos to the Photo Gallery (Photos) app logo that looks like a rainbow flower.

The problem started when I tried to change the "user" name which was user to something better. As soon as I changed it, I lost "admin" status and became "standard". Then I found a way to re-boot and to set up everything just like new. So, I created a new account as "admin" and Macbook saved account the one which I had which was "standard" I thought I can delete, so I deleted by picking up 3rd option "Delete the Home folder". Everything was perfect until the moment when I realized did the "iCloud" downloaded my pictures which I dropped to Photos app to the account which was at the beginning?

I remember when I was trying to rename user name, I didn't see any email accounts which belongs not to me. I know my biggest mistake not checking iCloud.  I thought if something will upload to iCloud it will be visible on the desktop screen.

My question is should I have to be worry about that my photos were uploaded to someone's icloud ?

Really need your advice Dear Forum Members and I'm sorry for my English, this wonderful language isn't my first or second language. Thank you in Advance.