Прошу посодействовать с проверкой письма по британскому языку! ( четвертной контроль)!!!

Прошу посодействовать с проверкой письма по британскому языку! ( четвертной контроль)!!! Может можно как-то сказать лучше, либо времена напутала, грамматические и пунктационные ошибки((


Moscow
Russia
13 May 2015

Dear Liz,
Thanks a lot for your letter. Sorry haven't written for so long. You asked me about my summer holidays. Well, in June I will celebrate my birthday! Then me and my litlle brother are going to visit our grandma. In July and August me and my family will be visiting our summer Cottage . But I'm not sure, I expect it's true. Okay, and what about you? By the way, I remember in your last letter You wrote me about a very Big book. Have you read this book? Is it interesting? Do You like this book?
Take care and keep in touch
With best wishes,
Julia