hi im a newbie in all this thing to become leaner, and now my pre workout meal is oat mixed with milk and 40 grms whey protein its this good? or should eat this meal after the workout, im only lifting for now....

Hello and welcome friend!

Well are you using a post-workout meal or shake? If not, then I would at least move this meal to after the workout, yes. Even better would be to leave this meal alone, and then have a shake after you lift weights. Try to use water, protein powder, and a carb source. I like dextrose and maltodexrin, some like fruits and some even oatmeal; I think my selection is best. :)

Also, don't have this post-workout shake after doing cardio, just weights.

How "pre-workout" are we talking?

It would be fine, however I'd prefer having the whey powder POST workout with simple carbs and having a normal, real food protein source (i.e. egg whites) with your pre workout meal.