You're in a pretty good position to make the jump to 150K, but I can understand your reluctance to commit to it. Maybe try writing down all the projects you expect to work on next year and see if that helps you make a decision. (I mean, I know I never stick to the project list I create now, but I know things like I'm planning 50K for NaNoWriMo and there's another ficathon I participate in and usually write 10K—so I can use those landmarks to help me start figuring out how many words I might write in a year.)