Not bad at all, considering it's your first head.
If your target is models for games then you better use other tools to model, because the path organic highpoly > polygon reduce > lowpoly is definitively not satisfying. You'll end up with poor looking models with still too many polygons. Modeling things with lowpoly in mind in the first place may be harder and less intuitive, but it's worth the troubles. It only takes a couple of good tutorials.
If your target is models for games then you better use other tools to model, because the path organic highpoly > polygon reduce > lowpoly is definitively not satisfying. You'll end up with poor looking models with still too many polygons. Modeling things with lowpoly in mind in the first place may be harder and less intuitive, but it's worth the troubles. It only takes a couple of good tutorials.