Mention wanting exclusivity by text or wait to talk?

The biggest signal is not what she has said about you but how the two of you move. If she initiates plans, responds within a reasonable window, and talks about things she wants to do later, you are probably on the same track. If replies are slow, plans get made only when you suggest them, and she keeps things vague, the relationship is still being tested on her side. Your question is only a yes or no for one of those situations.

Look at what has happened, not at what you hope is happening. Three dates with a clear plan for a fourth is a different situation from three dates where you have only ever talked about the next one the day before. If you are the one doing most of the work to keep contact going, that is worth noticing before you ask for anything bigger. Exclusivity is a question about shared commitment, and you can only ask it honestly if the commitment already has some shape.

If you cannot tell, that uncertainty is itself information. It usually means the question is still early.

A good text on this topic does two things. It says plainly that you want to be exclusive or are moving toward it, so she is not left guessing. And it leaves her space to answer in her own time without feeling cornered into a verdict. Those two goals pull against each other, which is why most messages go wrong in one direction or the other.

The way through is to name your own position and then ask a question she can answer honestly. Say what you have noticed and what you would like, then ask where she is. Avoid framing it as a test she has to pass. Also avoid burying the point under so many qualifiers that she cannot tell what you actually want. If she reads the message and feels both clear and unhurried, you have done the job.

Do not use the text to decide the outcome. Its job is to open the conversation, so that whatever she says, you learn something real.

Send the text when you are not already anxious and when you can take either answer. Late at night, right after a date that went well, or when you have been stewing all afternoon, is when people send something heavier than they meant to. Mid-morning or early evening on a weekday tends to read as considered rather than reactive.

Give it a day or two. If she replies warmly and engages with the question, that is a green light to talk about it properly, ideally in person or on a call. If she replies with something short and noncommittal, do not chase it with a second text pushing for a clearer answer. Wait for the next time you see each other and let the conversation happen naturally. If she goes quiet for more than about a week after a message like this, that is her answer for now, and continuing to send texts will only make the situation worse.

When to stop is when you have asked, she has told you where she is, and the answer does not match what you want. That is a fair place to stop pursuing it and decide whether to keep seeing her as she is.