How do I tell her my girlfriend I would love to have kids in the future with her?

The reason for having children has changed over the years. While it was GOOD to have MANY children 100 years ago, today it's best to have one or two. Many years ago, all the children would not live, because of diseases and fires and cold. Today we have many cures, fire and smoke alarms and heating. All your kids would help on the farm, or to BUILD the farm. Today your kid is likely to move out at 18, and look for his or her own place. If you have one child, you can save up for that childs education (very expensive). As soon as you have another one, then the first childs funds get cut in half. Now you have to get 2 computers when they get older, 2 phones, 2 of everything to be fair. If you have a third child, you will NOT be able to afford to send them all to college unless you're rich. So if you want to have a child NOW, realize that you have to have a plan, too. How many WILL you have? How close in age, so they can have company as they grow. Start a college fund NOW, so you'll be able to afford college if they choose to go. As soon as you DO have a child, your life is GONE. You will never have it back again. You will live everyday and every minute for that child and if you don't, you are irresponsible and should be jailed. So good luck with your child, but DO plan on being able to give them a good life.

You dont need to make a story to go with it.

If your relationship is strong enough, you should just be honest.