Hello there.
There are plenty of people you might want to talk to: me, Ingsve, Hrakkar, Mad Latinist, Sunquan ... even David J. Peterson himself. Possibly also some newer or less visible people.
Some reality check notes, though. People often have a bit off presuppositions.
1) Dothraki is one language, Valyrian is a family of closely related languages (or distant dialects) to which Dothraki does not belong to. We are more or less familiar with High Valyrian, Astapori Valyrian and Meereen Valyrian, but know that there are others, most notably the languages of Free Cities.
2) Valyrians and Dothraki are all developed by one person, Mr. Peterson. We here on the forum are not involved in the development (save for some random conversations and feedback that might have given an idea or two).
3) Fluency in a language is very hard to achieve, fluency in a not-even-fully-public conlang is a much harder goal still. Some newbies have fluency as their initial aim, some old ones hold it as a distant target, but mostly we have humbler or just different goals.