Olga is ten.
She is tall, thin and nice. - перед прилагательными без существительных артикль не употребляем.
She has got big brown eyes and long fair hair. - артикль не нужен, eyes мн.число
Olga is kind and friendly .She is very clever.
She can play the piano and she can write poems.
She has got two sisters. Lena is thirteen. She can speak two languages, English and French. -обязательно с большойбуквы, для англичан это важно и считается грубой ошибкой.
Masha is eight.
Little sister is a bit(чуть-чуть) noisy and funny.
She can sing and dance.