Is it too much to message twice in a row after no response

In the first 2-3 hours, silence usually means nothing. She's working, in a meeting, or her phone isn't in her hand. Send that first message and move on.

After 12 hours, silence starts to mean something. She's had time to see it and decide. If she hasn't replied by now, she's either low interest or slammed. A second message might land fine, but it won't change her actual level of interest.

After 24 hours, a second message is more of a Hail Mary. At this point, she's made a choice not to engage, even if she doesn't mean it that way. You're not rescuing the conversation by sending another one. You're just confirming she's not going to reply.

Don't try to re-engage her or ask why she didn't reply. Don't make it clever or funny. Don't apologize. Instead, add something new to the conversation that doesn't depend on her previous reply. Say something brief that stands alone and gives her a low-pressure way to respond.

For example, if you asked a question and she went silent, the second message isn't a reminder. It's a different, smaller observation or question that moves the conversation sideways instead of doubling down on what she ignored.

If you send a second message and she reads it without replying, that's your answer. Don't send a third. Reading it and not responding means she saw it and still chose not to engage.

If 48 hours have passed since your second message with no response, stop. You've given her two chances. Continuing to text looks like you're not reading the room. If she comes back to you later, great. But your job now is to move on and focus elsewhere.