In my opinion, yes, it’s #ownvoices. You don’t have the exact experience of a biracial MC… but you ARE [x-heritage], and if you are American, at least, you have probably been steeped in “white culture” your whole life, so I’d wager you know a lot about BOTH sides of your MC’s background. 

Being bi-racial of course might bring up concerns/questions for your character that are not identical to your own concerns/questions - but like, that’s fair - your main character is her own person, and that’s where empathy comes in. And I think it is easier to be empathetic and write a fully realized individual character if you are coming from a place of bone-deep knowledge. Which you are.

I mean, look - unless you are literally writing your own memoir, no main character is going to be a carbon copy of you. That’s not how books work (and frankly, if it WAS, it would be boring - most writers, bless them, really like *sitting in a room writing*, which doesn’t make for the MOST compelling adventure story!) I think OwnVoices is more about, do you have the authority to write a certain culture with confidence. And you do.