It looks like you’re off to a good start and I’d agree with the other’s advice above! The only other thing I’d mention is that you can get away with far fewer polygons than what you have now. Beginners almost always overcomplicate the topology, and understandably so because it looks better while you’re working, but it makes everything take way more work than necessary on top of it already being hard to learn. Keep the retopology as simple as possible and let the subdiv do the work of smoothing everything out. Good luck!
