Thank you for your post as we're sure a LOT of students have the same concern!
There is no magic number to aim for on your first Practice Tests. In the early going, the purpose of the Practice Tests is solely to increase your familiarity with the MCAT (interface, time constraints, topics emphasized, question types, etc.) and nothing more.
Regardless of your circumstances and academic background, you should be prepared to score very low on your first Practice Tests. Don’t be discouraged. It means absolutely nothing. Remember, you’re being measured against candidates who had finished months of studying and practicing. You’re just getting started so you shouldn’t expect to be competitive so early in the process. The MCAT wouldn’t be much of a challenge if you could get a high score without months of preparation and practice.
Moreover, the Altius Tests - like the Examkrackers In-Class Exams - are slightly more difficult than the official AAMC exams.
In short, ignore your early scores. If you work hard – practice, practice, practice – your scores will gradually improve.