https://www.homebrewtalk.com/f39/fermentation-can-take-24-72-hrs-show-visible-signs-43635/, and by visible signs we don't necessarily mean a bubbling airlock.
It IS a sticky at the top of the beginners forum for a reason, afterall.
You should really have made a starter for any beer above 1.020. The biggest reason I suggest folks make a starter is if you make one
you'll have peace of mind.
Making a starter first insures that your yeast is still alive and viable before you dump it in your beer. You will be less likely to start one of those "is my yeast dead?" threads that are on here every day.
You will also ensure that you have enough yeast usually the tubes and smack packs are a lot less yeast that you really should use for healthy fermentation.
Making a starter also usually means your beer will take off sooner, because the first thing that the little buggers do in the presence of wort (whether in a flask or in a fermenter) is have an orgy to reproduce enough cells to do the job...So it won't take such a long time in the fermenter since they started doing it in the flask.
Additionally it is better for the yeast to consume and reproduce incrementally rather than just dumping them into the fermenter...The yeast will be less stressed out than if you just dump them in.
Stressed out yeast can lead to a lot of off flavors...maybe even (though rare) the dreaded autolysis....Or the curse of 1.030....getting a stuck fermentation because the yeast have bit the dust.
So making a starter proves your yeast is still healthy, allows you to grow enough yeast to do the job, cuts down on lag time, and ensures that you will not get off flavors or stuck ferementations from stressed out yeast.
But the bottom line is that it is too soon to worry yet. Oh and by the way who cares if your airlock bubbles or not. It doesn't matter whether or not you have a single bubble in the airlock. It's not a magic fermentation gauge, it's a VALVE, and vent to release EXCESS co2, and to keep your ceiling from being painted by your beer. It doesn't matter one whit, whether or not you get a single bubble in your airlock. Plenty of beers ferment without it happening.
If you are really worried, THEN after 72 hours take a hydrometer reading then you will know.
The only way to truly know what is going on in your fermenter is with
your hydrometer. Like I said here in my blog, which I encourage you to read,
Think evaluation before action you sure as HELL wouldn't want a doctor to start cutting on you unless he used the proper diagnostic instuments like x-rays first, right? You wouldn't want him to just take a look in your eyes briefly and say "I'm cutting into your chest first thing in the morning." You would want them to use the right
diagnostic tools before the slice and dice, right? You'd cry malpractice, I would hope, if they didn't say they were sending you for an MRI and other things before going in....