Hey!
This is an incredibly good problem to have if I can say so myself!
For one, yes, you can just cancel everything and refund your backers.
However, since you're already funded and that "pressure" is already off your shoulders, you can also turn the next 50+ days to do more with and for your customers.
For example, since you already have 22 people backers, what about asking them if they want any stretch goals? They might even give you ideas for some new pins you can make AND also increase their pledge in order to pay for it too! All you have to do is ask.
You can also take this opportunity to start expanding your future customer base. I'm sure there are a lot of other people out there who want to learn from you and how you got funded with your pins so quickly. Take this time and the energy you were going to use to drive people to fund your project and put it into networking with others who are also pin creators and/or might love the types of pins you're creating. By doing that, you'll already have the "social proof" that you're legit and can find more supporters along the way!
Lastly, with all this time and already knowing that funds will be coming your way after the project, you can even get a head start working on your pins. That way, once the campaign does end, people can immediately confirm their address and you can ship them out right away! Even better yet, you can showcase backers the entire process during the campaign. That level of transparency will elevate most people into becoming your superfans
Hope this helps!