Trimming is personal thing. You can trim now if you wanted to and it really depends on your beard goals. My first trim was at 9 weeks. If you like a short length full beard, then introducing trimming now is an option. Even if you want to grow longer you can trim along. There are trim and grow techniques. All you need is an electric trimmer and some guards. Start with about .5 inch and then every couple of weeks increase the guard length until you find a length you like. If you want a big/long beard, then when you reach the longest guard setting then you can let the beard grow longer and maintain is with scissors and a comb. There are a lot of way to go about growing a beard. Hope this makes sense. Let me know if you have questions. Have fun!

Best,

Erik