How long do you wait to hear from someone before you cancel plans?

Ok, so my friend texted me today to see if I wanted to get together tonight. I said that I would be home at 5, so any time after that would be good. She has two kids & I know she gets busy, so I didn’t text her as soon as I got home. I contacted her around 6 to tell her I was home. I didn’t hear from her until almost 2 hours later!! She didn’t even say she was busy or anything, all she said was “where are we going” like I just spoke to her 2 seconds ago. At that point I didn’t want to go out anymore & asked if we could reschedule. I guess she’s mad because she never answered me back. But, tell me do you think I was wrong to cancel after waiting almost 2 hours to hear from her? How long would you wait? Lol