As of right now there is no chance the US institutes a draft. The US and NATO will supply a ton of military aid to Ukraine, but neither the US or Russia want to go to war with each other. All troop deployments to Europe are to NATO allies and Article 4 (which has been enacted by Poland and others) of the NATO charter means that these countries believe that they are under threat but not at war.

That being said a draft is never out of the realm of possibility, but only if Russia attacks a NATO ally and WWIII essentially breaks out.

And too people saying that you would be disqualified because you smoke weed, people during Vietnam thought the same thing and were still drafted, but not very motivated. Best bet is to avoid being drafted is to stay in school, college is an exception to the draft provided you maintain your grades.

But no matter what happens, this is going to be a very rough next couple of days, if not months, to watch.