Watermelons!!!!!

So my dad planted watermelon seeds and after about 5 days a vine started growing (a very long vine). Then about a week later 5 little tiny watermelons starting forming and my dad said that 4 of them fell off so 1 left. It's been on the vine for about 2 weeks and it sprouted from little tiny to that thing overnight (I think). It's right in front of my mom's room so we just walk out and see that thing. There's also one near it that's still tiny but hopefully it grows.