@Andy *********
, it is all just a matter of time. It is a long process. They also check on you, and if you are able to take care of her financially while in the US.
What I would actually suggest, is going to the district office and actually get married legally, and registered. Then apply, and at the same time apply for her Green Card, to legally stay in the US. It can take longer, but it worth it, and currently why go anywhere else. Thailand is the safest country to be in right now concerning this virus. Age makes no difference. My good friend was 35 years older than his wife, and after 14 years they are still happily married. The big thing they look at is her reasons to return to Thailand, and not just stay in the US. How close is family? Does she own property. Those kind of things. That's why I recommend actually legally getting married. Lots of those concerns disappear, and then it just becomes a case of moral character, and your pictures together, in many different places, means more, in that it is not just a scam marriage so she can get into the US, then you both ho your separate ways. You have to remember, the US is still a very desirable country, and the dreams of lots and lots of people.