Yep, the toy sounds huuuuuge!
Also, it's easier to accommodate a penis than a toy, cos human flesh is more..um...flexible, and will move with your natural contours. I wouldn't worry. I've had three children (ahem) and I wouldn't use a toy that size! I'd be terrified! Maybe get a little bullet type toy and insert that a small way to begin with. And, sorry to be so graphic, but if you can fit two fingers up there you'll be fine