what does "find her center"mean?
She unrolled her own mat, sat. When the others did the same, the fist clenched in her belly loosened a little.
Though she couldn’t find her center, her balance, her own sense of calm, she took the class through the hour.
Maureen lingered after the class ended. Abra expected no less.
“Your place or mine?” Maureen asked.
“Mine. I have a cleaning job in an hour, I need to change.”
“Good. You can give me a lift. I walked.”
“Sundaes last night?”2.what does "expected no less"mean?

Question

what does "find her center"mean?
She unrolled her own mat, sat. When the others did the same, the fist clenched in her belly loosened a little. 
Though she couldn’t find her center, her balance, her own sense of calm, she took the class through the hour. 
Maureen lingered after the class ended. Abra expected no less. 
“Your place or mine?” Maureen asked. 
“Mine. I have a cleaning job in an hour, I need to change.” 
“Good. You can give me a lift. I walked.” 
“Sundaes last night?”2.what does "expected no less"mean?

Answer

by center it means inner clam it does not mean a real center you can find like the center of a city but a metaphor for inner peace and expected no less means that they thought the person  was going to do that because they normal do that like say you have a friend that hardly answers the phone if you can you expected no less that they don't answer

Answer

A lot of times, "finding your center" means becoming at peace with one's self. It's about being calm, balanced, and centered. "Expected no less" means she expected or anticipated that, at the very minimum, something specific would happen. In this case, she wasn't surprised that Maureen lingered because she expected her to stay after.