Is this woman flirting with me? I do like her but im not sure?

This older woman in my building is so friendly with everyone. First time i met her she was carrying stuff so i went to herand opened the door for her. She thanked me and kept talking and she didn't make a lot of eye contact but she kept smiling. Few months later i was leaving the elevator and she was there waiting instead of going in she smiled at me like she is happy to see me i said hi how are you but she didnt say anything she just stood there smiling and i walked pass her carrying stuff i turned around she was looking at me smiling then she asked me if i need help i told her im ok and thanked her. Few months later i came from work and she was there checking her mail she looked up she found me staring at her she was wearing nice work clothes and i found her pretty she smiled at me i smiled back then a woman talked to her so i left. Is she flirting or friendly?