Ski lessons at Lake Tahoe for a 14 year old first time beginner?

What are the good places where our 14 year old can go off safely with
the instructor for a lesson and learn comfortably?
Do we need to invest in semi-private / private lessons or are group
lessons fine?

We are planning to spend 2-3 days (weekdays, not weekends) on the
slopes and some of the places being considered are Sierra at Tahoe and
Heavenly (expensive?);

No one at our home knows how to ski and we will appreciate any
suggestions that you can pass on;

Thank you,
AS