Am I selfish for not helping my coworker?

My coworker Des texted us at 4:37 pm in groupchat messenger that she can't go to work today because she felt dizzy. Our duty is 6pm-6am. She texted us if anyone can replace her schedule today. I replied "I can't because I live in this town ____ and I travel 2 hours from home to work and I still haven't showered and prepared and I will be very late at work if I come to work if only she texted us earlier I might help her" We have rules at work that 3 lates you're out 3 lates you're automatically fired from job. And I already have one late before and I dont want to risk my job for another late to save her. And another day off today Jen replied she's also in this town___ and she will also be late if she come to work. And then Des replied to me" she will pay for my late" I replied "Maam I can't because I will be late since its 2 hours travel and still haven't showered and prepared. Since the duty will start at 6pm she texted us at 4:37 pm"
And now Nica another coworker who is duty today she's morning duty before Des texted me I saw that shs already read my explanation on why I can't replace Des and she still dm me saying my name and that how many hours is my travel to work? I explained it to her that its 1 hour and 45 minutes almost 2 hours and that I still haven't showered and prepared. If Des informed me earlier I can help her. She just read my text.
I told my mom about it and she said Nica is kinda baiting me to get late so that she can save Des so that I get fired.
(I already have 1 late if I come to work today to save Des I will have 2 lates and in our job only 3 lates and you're out of job like automatic fired)
I can see because Nica and Jen are same town also I noticed back then they are both working same duty while me its only me on my duty like how is that happen 2 person working on same duty like they can help each other while me Im always alone at my duty. I can sense why Nica is trying to save her too. Nica wasn't nice to me too when I make mistakes
Am I selfish for not helping my coworker?
Updates
1 y
This is when Nica called me out in gc. What to do with my bossy coworker? And demanding doctors? ↗ my mom said she's baiting me to have a late so that she can save Des so that Im near to getting fired
Am I selfish for not helping my coworker?
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