We suggest you purchase a harp with at least 26 strings, and preferably one that can sit on the floor (either because it is tall enough or with a stand).
It makes it easier to balance the harp, which results in more relaxed playing and better hand position for you.
For more info on how to choose your first harp, take a look at this article and video: https://www.learningtheharp.com/buying-a-harp-everything-to-know/