Meditative is an adjective... but we do not use this a lot.
We use the verb, Meditate, more often.
We also use the adverb form, Meditatively.
For the adjective, I would use thoughtful, pensive, quiet, reflective.
Katsu sat quietly on a futon, meditating. She was pensive and quiet as she sat and watched a bird outside. Katsu often meditated in front of the window, quietly, thoughtfully watching the birds outside. Meditatively, she thought about the bird. She was reflective as she thought about the bird's life. She had a thoughtful mediation session, sitting pensively and calmly. She stood up and began her day, still meditating on what she had seen.
She heard a sad news, but she was not sad.
She heard sad news, but she was not sad.
She got a happy letter, but she was not happy.
She got a welcome letter, but she was not happy.
Perfect again! The letter was very welcome, she wanted it to come to her, she welcomed the letter like she would welcome her friends to her house.