How late is too late to text message a senior citizen at night? And how early is too early to text a senior citizen in the morning?

I sent a text message to a friend of mine who is my age along with a few pictures. I texted her at 9:15 pm and now she's mad at me for texting her so late.
Is 9:15 really late?
How late is too late to text message a senior citizen at night? And how early is too early to text a senior citizen in the morning?
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