vYu223,
I think a Downtube Mini, is the good choice, price, versus versatility, that's the one you need.
5 feet and 4 inches tall (may still have room to grow taller), 135 lbs <<<< OK
Purposes: <<< ALL
Preferences: <<< portable bikes good wheel size is 16", 20" better but not so portable.
Maintenance: <<< Use but not ABUSE OK
Spare parts: <<< OK standard
spending limit is $150 to ~$500-$600 <<< OK
Regards