My max is a 350 lb back squat at a bodyweight of 178. Not overly impressive but it's 3 plates
Cosign
@BillBanneker and
@The ADD as far as consistency, frequency, and a solid strength program. Starting Strength is great for beginners, Texas method 5x5 and also RPT training are two of my favorites for intermediate gains, and I'm currently doing 5/3/1 which is a great coasting/advanced/I like doing other physical shyt besides just lifting heavy program. If you're not doing 3 plates yet then you should probably be looking at starting strength or texas method (or any other 5x5, I hear Stronglifts 5x5 is good too).
Depending on your height, weight and current strength levels you might get to three plates before the year is over, or it might take slightly more time, but if you're consistent with your workouts, with your diet (eat whole foods don't get fukked up off the liquor every weekend, minimize processed and fast foods), and sleep (8 hours a night consistently), you'll be there in no time.
Two more things: First, stick to whatever program you're doing above all else, but pause squats are something that you can consider throwing in on some of the lower weight work sets (especially in 5/3/1 if you're doing first set last sets, that'll make sense if you read the book). I'll generally do like 3 sets 8 first set last squats where the first 3 reps include a 3-5 sec pause. And I mean a full one-mississippi, two-mississippi, three-mississippi, four-mississippi, five-mississippi count, don't cheat yourself. Having to pause in the hole builds alot of stability in that position and gives me way more confidence when I'm going down there with heavier weights.
And lastly, 3 plates ain't even that serious. Sometimes you make these plate goals a big thing in your mind and psyche yourself out but when you finally break past it you realize it wasn't shyt. I used to think 3 plates on deadlift was insane and now I do that as part of my warmup/early work sets. Wrap your mind around the fact that this weight you think is crazy will be light weight for you in time as long as you're doing the right things. Just focus on consistency above all else with the important things (gym frequency, diet, sleep) and the results will inevitably come over time.