Now she is in a normal school with sixteen in the class. It is stressful but she can manage.
But how many normal schools have a class size of 16? At our elementary school it's more like 32.
Do I understand right that in the US or in the UK she would have been sent to a normal school right away, as there don't exist any special needs schools...
I can only speak for Canada and the US, but yes, special needs schools do exist, however children with disabilites who are deemed to profit by attending a normal school would have something called a special education teacher in the classroom with them as well as the regular teacher. The special ed teacher works with the disabled kids individually or in groups and helps them keep up. I don't think that exists in Germany.