Is it weird to text her if she only texts at night?

Look at when the texts happen and what they are about. If every message arrives between 11pm and 2am, it is a habit tied to her evenings. She is off shift, in bed, scrolling before sleep, or the only time her day slows down enough to text. That does not tell you whether she likes you. It tells you when she is free. Now look at the content. Short, joking, low effort messages that die after a few lines mean she is keeping the connection warm without committing time. Longer messages that ask about your day, your weekend, or what you are doing tomorrow mean she is building toward something. Your own pattern counts too. If you have only ever replied at night, she has learned that night is where you two talk, and changing that is a small, reasonable move.

Asking about the pattern turns a fun exchange into a defense. Whatever she says, she has to justify her schedule, and you have spent your message on her habits instead of your interest. Keep the message about something you would actually like to know or share. Match her tone, so it does not read like a formal invitation sent to someone who was joking. Give her one easy thing to answer, such as a question with a clear answer or a plan that needs only a yes or no. Mention the time of day only if it helps, for example by referring to something you are doing in the afternoon. Avoid stacking two questions, because she will answer one and skip the other, and you will read that as disinterest when it is just how people reply on phones.

Send the daytime message once, then leave it alone for a full day unless she replies. Two messages in one afternoon look like a chase, even if you meant the second as a follow up. If she answers during the day, that is useful, because you now know daytime works for her and you can aim for it again. If she only replies that night, answer that night in a short, light way, then return to daytime later. If she does not answer by the next day, send one more message that is easy to answer and makes no reference to the silence, such as a plan with two options. If that gets no reply either, stop. Silence after two tries is information, and continuing to text after that usually makes you the one keeping the thread alive.