@Fabian608 How did the guest contact you? I don't understand what you mean about the credit score: can you not rent your place to whomever you wish, provided that they have satisfied whatever requirements you have for payment and references? It sounds to me like there is something fishy going on. I would definitely be asking a lot of questions. Scammers often prey on newer hosts.
If you're willing to consider hosting this person, I would research how long it takes for a guest to get tenant's rights in your jurisdiction. That's always my concern with longer stays. In my province, a guest becomes a tenant after 30 days, which means you would need to go through a formal eviction process if they reached the end of their stay and refused to leave. In my area, all evictions have been suspended due to the pandemic. If the situation is similar where you are, it could potentially take a very long time to get this person out.
Airbnb really isn't well suited to longer stays. You have no proper lease with the guest, and no real security deposit. If the guest trashes your place, you have no guarantee of getting money for repairs or cleaning, and a guest could do a lot of damage in three months.