First time calling out

I’ve never called out before and I am always staying a few hours later or coming in a little earlier whenever they need extra help and or if someone calls off. I had to call out recently due to change of plans and I let them know one week ahead I couldn’t come in on a certain day. I was only able to find one person to partially cover my shift and I was marked as a call out. I know this is generally the policy but honestly this makes me never want to come in earlier or stay in later ever again for other people calling out. Is the general rule 11 call outs and you get fired? I’m a part timer (even tho I’m pulling in 30-35 hours a week from coming in early and staying later :) ) so I don’t have sick leave or PTO.