Is there any way to whiten teeth with with out baking soda?

Yes: There are whitening products safe for teenagers that can be dispensed by your dentist. Check with your dentist

Whitening for 11 yo?: Have your daughter's dentist examine her brushing habits as well as health of teeth and gums and then discuss whether or not it would be appropriate to try to whiten her and if so, what would be the best method. There are many mild to strong whitening products and techniques, both in office and OTC. Unless a real problem, whitening for an 11 year old?

Teeth whitening: You can use over the counter tooth paste or crest 3D whitening strips or pens. However, they are not so effective and/or stable. OTC bleach and whitening tooth paste could be used as a supplement only. A professional home whitening system with custom trays for the long term effect. You will be very happy with the results.