Transitioning from writing tone marks to ignoring them—is this bad?

I’m currently studying for a proficiency assessment and I’ve noticed that in most WhatsApp messages or casual texts between Yoruba speakers, the tone marks are completely omitted. I’m worried that if I start ignoring them for speed, I’ll lose my ability to distinguish between verbs that differ only by tone. Should I stick to marking everything to ensure accuracy, or is it better to learn to read 'unmarked' Yoruba early on?