Why is she blowing hot and cold?

I got back with my ex girlfriend a couple of months ago. I dated a few other girls in between but I realised that I missed her like crazy so we decided to give it another go. Sometimes when I think it’s going amazing, she pulls away and things are not so amazing again. There were a few reasons why we broke up. Mainly it was due to my busy schedule at work – which meant we didn’t communicate often, and the fact that we live in different cities – which made it difficult to see each other. I’m 28, she’s 24. She’s a very sweet, sensitive, lovely girl, and slightly ditzy, but I find her a bit of an enigma. It kind of make her attractive but it’s very frustrating when she blows hot and cold…

Hot:
– The way she looks at me, that look in her eyes.
– She is very affectionate. She strokes my face and my back, and kisses me all over.
– She never refuses sex, in fact she is always the one who wants it.
– She said she hasn’t slept with or desired anyone else since we broke up.
– She once cried when she had to catch her train home after spending the night at mine and said she wanted to stay.
– The same day she told me ’‘I love you” for the first time since we got back together. I said it back to her, but the main thing is she said it first.
– The last time I saw her she said she was worried someone closer to where I live will steal me from her.
– She never refuses to see me and never cancels any arrangements we have.
– She has said she has never loved anyone as much as she loves me.

Cold:
– She replies to every text I send but she NEVER initiates texts. I’m always the one having the text her first. I’ve someone’s gone 2 or 3 days without texting her to test if she would initiate but she never does.
– She sometimes goes funny when I give her compliments.
– She also goes funny when I bring up the subject of children or her having a “maternal side”. She just gets uncomfortable and says she’s not maternal at all.
– When I mention that my parents and friends love her she goes weird and says they don’t even know her that well.
– She has sometimes says that she thinks it won’t work with us because of the distance.
– She has said that she thinks we are very different people and an odd couple.
– She has asked why I don’t go on dates with other women.
– She doesn’t get jealous at all. When I told her a story about me going to a strip club last week… She just burst out laughing (I say this, but she DOES get jealous of my exes and the girls I dated in between her when I mention them).

What do you guys think of her behaviour? Are there any major red flags here I should be concerned about or are they just small issues that I’m making a big deal of?