Need to clarify things with your help

I have since backed off and the previous girl and I are now good friends.

Another girl, from my horticulture class, started asking me about future plans and it got into future hobbies. I am curious if this sounds like playful flirting or ¨I really like you¨ flirting. I also would like to know if my actions are okay during this time. My latest action (on tuesday, the day we left to robotics) I wrote up a nice, well writen and pretty obvious kindness letter (a thing they are doing at school) to this girl.

Considering my lack of understanding my last issue (which I apologize for, I was in denial and didn´t realize I was still in it). This time I am open to all suggestions (but try not to leave too much of the sugar coating off)