I just joined the PDGA after playing in two very recent tournaments. Are those tournaments usable for ratings and if so, how do you submit them to be considered? Or can you only go forward with ratings, meaning I must wait until I play in the next tournament to be rated?

Make sure the TD has your new PDGA number so you'll get ratings once the reports are turned in to the PDGA. The next ratings update is May 4th and you'll see your rating then if any of those reports got turned in.