Congratulations on your new little one!!! I can imagine your shock and joy this morning when you went out!!! So very, very grateful that all went well. She is absolutely gorgeous and I am so happy for you.
To answer your question it could be your mare was just wary of you, But yes it is something you should be concerned about. Your filly must drink and absorb colostrum within her first 12-24 hours.
The immunoglobulins can only be absorbed by the foal's gastrointestinal tract during the first 24 hours (the peak time for when the intestine can absorb the most is within the first eight hours of the foal's life). After that time her intestinal tract cannot absorb the larger immunoglobulin molecules. After about eight hours of the newborn's life, the absorptive capability declines steadily to zero, around 24 hours of life.
Since you said she is attentive to the foal...the photos say she Loves her! I will hope and pray that the little one has already nursed. Will the mare allow you near her? Don't worry too much if she won't, Mother Nature works very well at providing all they need.
I agree since you've seen her pee that is good. Hopefully she has (or will) pass her meconium as well...this is also very important.
Please let us know how she does, if she's nursing etc. Please ask any questions you can think of, hopefully we all can help. Enjoy your new baby!!