What is my ex thinking

Hey, Could someone please give me some advise on my current situation as I am really unsure what to do. My ex and I broke up about 5 months ago first couple months were really hard for me not being able to accept the breakup and everytime I saw her I was trying to get us back together. I decided then to space myself from her and focus on dealing with what happened, this is difficult because we have a 3yo whom I see on a regular basis. Any contact during that period was strictly to see my son and the conversations were very short.
After a few weeks of this she started calling/txting to make excuses to come by and get things she had left ect. By this time I did feel a lot better emotionally and allowed it, we hung out and these occasions started increasing. For the last couple months we have been talking and spending time together regularly. It has been great, no physical intimacy, but flirting and touching..
I was telling a mutual friend this and I though that we may start dating again (we are going on a date in 2 weeks when I get back from work) and be taking things slow. She informed me that recently my ex met a guy who asked her out for dinner. My ex told him lunch would be better (she felt dinner was too formal) and she was quite hesitant about going out because she was happy with the balance of things in her life but decided one date couldn't hurt.
My question is I thought things were going well between us but she is now about to go on a date with another guy is this something I should be concerned about, like she isn't feeling the same way as me?
Or it is out of my control and let it happen hoping that she does one date and it goes nowhere from there. Like maybe it helps her decide that I am the one she wants?
When I wasn't limiting my contact with her I went out on a couple dates to get over her but all it did was re-enforce the fact that I love her and she is the one I want to be with.
I do realize we aren't together and she has every right to go out with other ppl, I feel stupid by our mutual friend telling me this when I thought things were going well.
All I want is for us to be a family again, I really miss it and hate seeing my son here and there.
Thanks for your help