But not Marcia, it sounds like Marsha which is awful .
It's pronounced as the prettier "Mar -see -ah" in some languages - I think "Marsha" just became more the go to in English speaking countries because of the The Brady Brunch TV programme/films
.
To be honest since Marcia is rarely used for more than 15 -20 girls in the UK each year, I think OP could easily choose which pronunciation she preferred and people would use it - it's like "Mar - chell- ah" vs "Mar -sell -ah" for Marcella.
Btw OP Marcie is rapidly increasing in popularity (I think people are looking for the new Marnie/Darcy), so baring that in mind, if you use Marcie as a given name I'd pair it with a "classic" sounding name as middle - Elizabeth, Alice, Charlotte, Isabel, Eleanor, Emma, Beatrice, Imogen, Catherine, Laura, Sarah, Julia, Lydia etc