Can anyone give me some advice?

Hello...

This is such a strange post but just wondered if anyone had some advice for me...

So I'm only 20 years old, I know I want kids but don't want them just yet.. I have been with my boyfriend for 3 years. 

Basically I came off the mini pill last June (2016) and there's been about 6/7 "scares" since. I know it's irresponsible but the more I wasn't falling the more I kept panicking and hoping I would fall even though it's not what we want just yet.

I am terrified I won't be able to get pregnant when I'm older as it's probably the one thing I'm most certain that I want!  

I just wondered if anyone (who has properly done this whole thing!) could give some advice, am I worrying too soon? I think it doesn't help as a lot of girls from school fell pregnant after one time! Unfortunately I'm a huge worrier as it is, and I know stress can help prevent you from falling...!

So if anyone could give me some advice as to whether this seems normal, it would be greatly appreciated. 

Thank you. x x