My condolences to you.
Adding to what others have said here, they wont let you read a poem up on the platform in the Kingdom Hall. But it would be possible in the crematorium or burial site if you make your intentions known beforehand.
Also be aware that in this time of grief, some well-meaning Jehovah’s Witnesses will more than likely use it as an opportunity to try and offer you a “free home bible study” and inform you that, as they believe, god promises an earthly resurrection where you can see her again.