Calendula is the daughter of Fluttershy and Bulk Biceps, she's a local nurse of the ponyville hospital

It was not a surprise that Calendula was a pegasus, with a similar problem with her father and even scootaloo : The small wings
Because of this and the surrounding of her life, she is more close to a earth pony, doesn't even know how to float in the air, whch wasn't a problem for her, of course
Calendula lived a very normal and comfortable life, with both of her parents being nice and careful about her, everything was going okay in her life

In the middle of her adolescence, Calendula lost her front hoof, which caused a very traumatic and confused mess in her head, making her basically live in the hospital, trying to adapt herself to walk this way

At this time, she basically just became interested at the place, she usually never was in one excepted for important check-up and medical recommendation for natural diseases, constantly worried about getting herself hurt again. Calendula became a volunteer in the hospital, always in the side of the nurses and learning about her new job

Yes, Calendula's ''destiny'' was to be a nurse, but the way she just became interested about hospitals because the excessive imagination of her getting hurt and knowing a place where she can learn ways to avoid it or take care about it just became a safe place to her

Her personality is a more neutral, tired and stressed, not trying to be the center of the attention and just constantly being a workaholic, but she has a gentle and kind personality in the inside that she learned with her parents, of course