Should I text her if she hasn't texted me in a week?

Look at the last thing she sent before the gap. If it was warm and open, with a question or a plan hanging in the air, her silence is more likely the ordinary drift of a busy person. If it was short, flat, or a bit disengaged even before she stopped, the gap is confirming what the thread already suggested. Don't read her silence in isolation. Read it as the end of a pattern.

Also check whether the two of you have been the one doing the messaging. If you've been initiating most of the time and she replies in long bursts when she does, a quiet week is normal for her. If she has been starting conversations and suddenly stopped, that's a clearer shift, and it deserves a more direct read. Either way, a week is not long enough to assume anything about how she feels, but it is long enough that the next move should be a light one.

There are a few broad kinds of message that work here, and they do different jobs. One is a low-stakes check-in that refers back to something specific from the last conversation, so it reads as you remembering her rather than measuring her. A second is a plain, unforced line about something you'd have told her if she were in front of you, with no question attached, which lets her respond or not without owing you anything. A third is a concrete invitation, used only if you already talked about doing something together and it still makes sense.

You can tell a draft is the first kind when it names a detail from her last message. It's the second kind when it stands on its own and asks nothing. It's the third when it proposes a specific time or place. Leave out any apology for the gap, any question about why she went quiet, and any phrasing that asks her to confirm she's still interested. Those turn a light message into a request for reassurance.

Send during the day, in the middle of a normal window, not late at night when a message can read as lonely or overthought. A text sent on a weekday afternoon looks like something you thought of, not something you've been stewing over for hours. If you've been checking whether she's online, don't send anything until you've stopped doing that.

Give it at least a few days before any follow-up, and if you do send another, keep it shorter than the first. If she doesn't answer after one message, don't send a second that is essentially the same question. That's the point to stop. Let her come back when she wants to, and if she doesn't, the conversation was lower-priority for her than it was for you, which is useful to know without you having to do anything about it.