Is there a way to check my warranty?

Hi Jere_Ana, according to the current policy, the warranty period for a product starts on the day such product is delivered, If you cannot provide invoice or other valid proof of purchase, then the warranty period will start from 90 days after the production date that shows on the product, unless otherwise agreed upon between you and DJI, please kindly note and understand. More details, please visit this link: https://www.dji.com/service/policy?site=brandsite&from=footer

DJI Susan Posted at 10-4 23:08
Hi Jere_Ana, according to the current policy, the warranty period for a product starts on the day such product is delivered, If you cannot provide invoice or other valid proof of purchase, then the warranty period will start from 90 days after the production date that shows on the product, unless otherwise agreed upon between you and DJI, please kindly note and understand. More details, please visit this link: https://www.dji.com/service/policy?site=brandsite&from=footer

I purchased my spark from someone who was reselling it in brand new unopened box. Would I still be able to be covered under the warranty? Is there a way to show proof like an aircraft activation?

You can, at least, check the manufacturing date;
http://tools.retroroms.info/
But without the original receipt, you would need to ask DJI Susan, to check on which date the bird got activated.
Otherwise: In case your bird got manufactured before August 2018, you are out, methinks

Jere_Ana Posted at 10-4 23:16
I purchased my spark from someone who was reselling it in brand new unopened box. Would I still be able to be covered under the warranty? Is there a way to show proof like an aircraft activation?

Have you activated the unit? Could you PM us the aircraft SN for double check?

Jere_Ana Posted at 10-4 23:16
I purchased my spark from someone who was reselling it in brand new unopened box. Would I still be able to be covered under the warranty? Is there a way to show proof like an aircraft activation?

Actually, in case you haven't activated it, the "unopened" box  was, perhaps, not so unopened?

How many times is the battery charged? Look it up in the app!

S-e-ven Posted at 10-6 00:10
Actually, in case you haven't activated it, the "unopened" box  was, perhaps, not so unopened?

How many times is the battery charged? Look it up in the app!

It was charged zero times when I first opened it. It still had the plastic sealing on it.