Complex sentence: While growing up in the Garston area of Watford, Smith regularly played football on boys' teams until, at the age of seven, she was kicked out of Garston Boys Club--despite being the top goalscorer--when the parents of her male opponents complained.
Split into simpler sentences: While growing up in the Garston area of Watford, Smith regularly played football on boys' teams. Until, at the age of seven, she was kicked out of Garston Boys Club--despite being the top goalscorer--when the parents of her male opponents complained.