How long have you been training? Because in your first 3-9 months, so long as you consume more calories than you spend, you'll grow - exactly how much protein you have isn't a big deal.
After that, it's as others have said - aim for 1-2g of protein per kg of bodyweight each day, and try to spread it out a bit - ie not just have a big chunk of steak for dinner and nothing else protein-wise each day.
The basic diet seems okay, but you have to just try things and adjust as you go - if you're trying to bulk, then if you
ever feel hungry you are not eating enough! Everyone is different, human bodies are not machines, "put X of Y in and get Z result."
I would probably put the 10am meal at 8am, you need a good chunk of carbs at breakfast to keep you going through to lunch. At 10am have something else, even if just a couple of pieces of fruit.
Take the three protein shakes and put them in one container, drink half just before your workout and half immediately afterwards. People are stronger when they work out, recover from workouts more quickly, and grow muscles quicker if they have the protein/carbs drinks before and after the workouts rather than throughout the day - just the way the body works. So you have to adjust as you go.
And it's a
protein/carb shake you want - roughly equal amounts of each. You can use your whey protein and dextrose (buy from the brewing section of the supermarket), or else just get skim milk powder, mix about 100g with 500ml of milk and a few eggs.
If you're a beginner, then you'll get the best strength and fitness gains from having cardio and weights on
alternate days, so three each a week and a day off. But if your main goal is to bulk up, ditch the cardio entirely. It tends to burn up the muscle a bit. Anyway as your muscles grow they'll burn more calories just sitting around.
Of course if you also want to be fit, then you need the cardio, and you'll just have to accept slower muscle and strength gains.
Also if you're in that first 3-9 months, you don't need to split up your weights routine like that. Just do a full-body routine each time, do a 5-10 minute warmup walking to the gym or treadmill or skipping rope or something, then go for the big compound lifts - in each session,
squat
or deadlift
bench press
or overhead press
bent-over barbell row
or chinups
with a light warm-up set, and then 3-6 heavy work sets for each. Then stretch afterwards.
Once you get good and strong on those basic lifts, then it can be useful to split it all up.
You are right that diet is most important, it's good that you know this, lots of people never get it, let alone at 18, well done mate!
Keep a workout and diet diary, this helps a lot in adjusting things, seeing what works for you and what doesn't over time. Also makes you feel more accountable to yourself, helps you keep things up.
Boxing is good for you, keep at it
Good luck!