Cross play form PC to Xbox with my own account

You can't play at the same time with the same account.

It now depends, if you both use the same account just for playing, or if you both have your own accounts, bought the game(s) with your separate accounts, and only play on the same account.

So first of all, make sure you both have your own account. One of you both keeps the existing account, and the other one creates a new account.

Before you do that, be aware of the following:

Game purchases are tied to that account that bought the game. You can NOT share the game to other accounts! You can only share to a console!

For example: You decide to keep the account that bought the Xbox Minecraft, and your sister wants to play on the Xbox One. Then you as the owner of Minecraft would set the console your sister plays on as your "Home Console" (under Settings->Personalization).
That way, your sister can play all your games on her account, even if her account doesn't own the games on your account.

If your sister keeps the account, and she bought the PC Minecraft on that account, she'd need to do the following:

If your sister is of legal adult age, she has to go to
https://account.microsoft.com/family and add your own account to the Microsoft Family account. If your sister is on a child account as well, have a parent add your two child accounts to the family.

After all your accounts are in the same family, sign into your own account on your PC.

Start the Windows 10 Store, and in the upper right, sign out of your account. Let your sister sign in with the account that bought Minecraft. Then download Minecraft 10 again through her account.

After Minecraft was installed, she signs out of the store and you sign back into the store.

Now you have Minecraft on your PC.

With two separate accounts, you can now each start Minecraft on Xbox and PC and join each other in Multiplayer.

Just be aware, that on the Xbox you need to play "Minecraft" without the "Xbox One Edition" in the name, to be able to play with PC and Windows 10 Minecraft!

Would this mean one of us would need to repurchase the game/xbox live?

The same account woll only require her to create her own Gamertag. You will not have to purchase the game again.

Hey Ty. Few facts here for ya.

1. Minecraft Xbox One version is NOT cross-play compatible. You will need to own Minecraft Bedrock as it is known as on the console to play with the Windows 10 version on PC.

2. I have successfully signed into my PC and my Xbox One and played on the same map with my account on the two devices at the same time. So yes it does work.

Link to Minecraft you'll need on Xbox One to cross-play: Minecraft

She needs her own account, but shouldn't need her own gold subscription as long as your account has one and has that Xbox set as your home console!