Dating a slow texter

[zincmagnesium8]

I've been dating this girl for a month now and have been on about 8 dates. They've all gone really well and we seem to get on great together. I haven't brought up being exclusive yet, but I'm sure it's not far away.

There's one thing that's slightly bothering me. She is very slow to respond to my messages. I know it may not seem like a big deal, but it keeps sending doubts into my mind. 

My normal dating scenario is that I might message a girl in the evening and have a conversation back and forth for a couple of hours before saying goodnight and then maybe chat again the following evening. With her, most times (not exaggerating) I've messaged her and she could be 6 hours or more before she responds. I know what you're thinking. She's got a busy life, right? She can't be expected to reply instantly and I'm not the only thing going on in her life. I would have given her the benefit of the doubt on that, but she teaches small kids for a living and her work day finishes at 2pm so she has a lot of free time on her hands. She also tells me a lot of the days she gets very bored. Despite this, she doesn't feel the urge to reply to my messages? I don't get it!

Sometimes it's no biggie and I'm just making conversation. Just grin and bear it. Other times I'm trying to make plans for the next day, so I'm left wondering if I have to book somewhere for our date, or should I make other plans. At times I come across desperate because I make sure to arrange another date almost as soon as the last one finishes so that I have time to deal with her slow replies! I'm sure she sees the messages come in because WhatsApp shows when someone is last online. Many times she's posted a story to Instagram after my message and before she replies to me so she's able to find the time to do that at least!

When she does send messages they're long and meaningful and in person she seems almost infatuated by me, which is great. But when she doesn't reply to an invite for a date when I know she's seen it, sometimes I feel like she's taking time to think it over and see if she has other plans, or maybe just end things. That's just my mind wandering, but it's not great for the morale when I know she could reply, but just doesn't.

Could it be that she's playing games and doesn't want to seem too eager? Is there another logic to why some women (and I assume men) behave this way?