Hi Sahana! 
Thank you for your question, and for feeling comfortable enough asking for our advice on your schedule. I think it’s great that you’re making sure you’re not overwhelmed in your first semester of college. 
As a premed, and especially starting out at the University of Michigan, it’s so easy to compare yourself to other premeds. It may seem like you’re doing something wrong when comparing your schedule to other students’. But it sounds like what you have right now is perfect for you and your goals. 
As for when to take intro bio (171, 172, and 173), I don’t have a set time for which you should take them, but I will say you should probably take them sooner rather than later. I say this because there are quite a few prerequisites you have to take for the Neuroscience major, so it’s better to get those out of the way so you can fulfill your major requirements. 
But for these prerequisites, here’s my advice: take them soon, but take them when you feel ready. Especially with bio and organic chem, the material may be a bit of a shock if you’re not mentally prepared; for me as a freshman, bio definitely took some getting used to. And of course, don’t forget to cast your net wide and take some courses that actually interest you! 
If you’re still feeling uneasy about your workload this coming semester, I would HIGHLY encourage you to connect with your advisor and the Neuroscience major advisors to discuss your four-year plan. But if you feel really excited about the classes you’re already signed up for, stick with them! It’s only your first semester in a long journey, and you won’t fall behind. 
If you have any more questions about your neuroscience major or the pre-med journey, we’re here to help you! 
Good luck Sahana! 
-Arjun, PMH Advisor