WHAT AM I SUPPOSED TO DO NOW THAT MY DREAMS ARE RUINED?!?1?

I have been a writer ever since I can remember (I am now 13) and at around the age of 11 I got a story idea unlike any other...It could even turn into a trilogy...only...last week I found at that there is already a novel that touches on the same idea...The Talisman by Stephen King...everything is the same...from the venturing through dimensions to the main character being a young boy trying to save his mother, hell, even to the beginning setting of a beach side apartment next to a fair...this story would have been the one that could get my name out there as a writer...if I continue with the story and just try and make it as different as possible...even thought it might still sound similar, would I be accused of plagiarism?