What to do when she doesn't reply for 2 days?

Look at what she actually left open. She said she'd talk later, and you had already agreed on a plan. That makes it an unfinished exchange, not a closed one. Silence after an open loop is almost always logistics, a busy stretch at work, or her phone being buried under other notifications. The question to ask is whether the thread still has a reason to exist. Here it does, because you have a plan that needs an address and a time.

Read the length and warmth of her last messages against the silence. If she was engaged, sent multiple messages, and used punctuation with energy, the gap is probably situational. If her replies were already getting shorter before she went quiet, the silence is more of a fading signal. In your example she wrote enthusiastically and proposed the idea, so this reads as a busy pause rather than disinterest.

The reply that tends to work restarts the conversation on the thing that was already in motion. You can do that in one of two ways. One is a practical follow-up that moves the plan forward, something she has to respond to only to confirm. The other is a light, neutral check-in that gives her an easy opening without asking anything heavy. Both work because they give her a reason to reply that doesn't involve explaining herself.

To tell a draft is working, check that it refers to something specific from the conversation and asks for nothing bigger than a yes or a time. If it names the gap, asks why she went quiet, or reads like a question about how she feels, it has drifted into the wrong kind of message. Leave out apology, leave out guilt, and leave out anything that sounds like you counted the days.

Wait at least a day after your last message before you send anything, since two days of silence already means she hasn't been thinking about the thread. Send one follow-up and make it the one that carries the most reason to reply. Then wait again, usually another day or two, before deciding anything. Sending a third message in a short window turns a normal pause into a pattern she'll notice.

If nothing comes back after that follow-up, stop texting about it. You can still leave the door open by letting her know you're around if she wants to pick it up later, but don't stack messages on top of each other. If she doesn't respond after two follow-ups spread over about a week, treat the thread as paused and move on. Keep the decision simple, because a quiet phone is information, and you don't need to win it back by sending more.