When they are youngsters, they generally think the right answer to pressure is to move faster. I don't mind them giving me a bit more speed as long as it's headed in the direction I asked them to go, at least at the beginning stages...given it's not walk to dead run. You can use light contact on his mouth if he is giving you too much speed, just enough to say "hey, faster isn't the right answer." then try again. It should be one fluid motion & small 'bumps' not constant pressure. Take a few steps, 'bump' him over, repeat. My mom told me when I was a kid that "It takes the average horse 100 times to learn something new before the light bulb goes off" Very true statement with most, some are a bit faster some not so much lol! Don't be too aggressive with your leg pressure, if he is already starting to move out a lot with any, try focusing on keeping your legs draped against his sides the whole time you are riding so when it's just a bit more pressure it's not as much as a surprise to him that you are legs on. Oh, meant to ask what you are riding him in. I would assume at his age you are 2 handing him in a snaffle. I like to use a 1/2 breed side pull on youngsters that get a little too forward, you have the added benefit of nose pressure with still having the snaffle & they seem to get it faster without having to worry about getting in their mouth, my goal is always to have a light horse with a soft mouth, so I find myself using the 1/2 breed quite often. Hope that helps!
Life is like a camera. Focus on what's important, Capture the good times, Develop from the negatives and if things don't work out, Take another shot.