Hello, I'd like to assist you with your question. Welcome!
I can understand your confusion in the way you describe the dynamics in this relationship.
She definitely shows interest, but it's unclear what sort of interest. Is she enjoying the fun, light and "flirty" interaction, and the attention that brings, or is she interested in a relationship?
Sounds like right now her preference is to communicate and maintain contact "from a distance", verses taking it to the next level and spending time together. She's a young woman who is a single mother, and works outside of the home, her being "busy" is certainly understandable.
"not a great past", there may be many layers to this woman and what she's dealing with. Right now she may be enjoying the validation and attention she gets from you- it feels good, and she may be undecided about the future of the relationship- or what she wants.
I think you have little to lose in calling her and speaking to her directly. Find out, if possible, what direction she sees this relationship going. This uncertainty and mixed messages will continue to cause confusion.
I think it sounds like it is worth your time to continue to invest some time and energy to get a better idea where this woman stands. She may be afraid- fearful of making mistakes she has made previously in relationships. The other thought/option would be to giving her some time, continue to keep it light, allow her to pursue you. If you were to pull back, you may get a better idea how invested she is, by how hard she works to keep you in her life.
The distance between the two of you may be complicating things too. I do get the sense that she is being apprehensive to commit to time together in person- "fear", is what it may be about. This certainly can look like "playing around"- but may be more about her fear of true intimacy, at least for the time being.
It's wise of you, as you are doing, to trust your gut on this. It's a good idea to protect yourself from someone who may be seeking more superficial/less committed, and less demanding, relationships. Being a single mother with her children to consider may also be part of this- getting involved with a man, and if that relationship becomes more serious, having to make decisions about how, when, etc. to involve her children.
She has experienced a lot in her 24 years- two children- and likely complicated relationships with the father(s) of her children.
Let me know if you have any additional questions, or need clarification on anything I posted. Thank you for your post. These affairs of the heart are sometimes difficult to make sense of with so many dynamics involved. It is wise of you to go into this with a sense of caution, being careful to decide if this is something you want to "sign up for". Have a great day! Jean