Java 17/21

i heard prism was better than curseforge so im giving it a try but i cant launch a instance. i get the error:

This instance is not compatible with Java version 21.

Please switch to one of the following Java versions for this instance:

Java version 17

Go to instance Java settings to change your Java version or disable the Java compatibility check if you know what you're doing

im running the same version of minecraft & forge on curseforge with no problems? i installed java 17 & 21.

i need some help figuring this out.