I am a terrible texter. It just takes me ages to reply a lot of the time and sometimes I outright forget. It sometimes pisses my friends off cos they'll see me online on Facebook and think im chatting to people but just ignoring them but really im watching animal videos and trying to distract myself.
She could just not be much into text conversations. Im that annoying friend that my friends tend to just call if they want an answer from me quickly cos I'll always answer a call. However, I will say im always trying a lot harder when im starting to date someone. However I haven't had to deal with being a teacher during lockdown, so, there's that.
The only way to know for sure is to ask her, it's more than likely she's just not a big texter and is stressed and busy. there's that small chance it's something else though, so I hope you figure it out!