I don't see any issues with how you've shaped your neckline. Good job! The true test will be if you are able to maintain this shape with continued growing.
Do you have a beard goal in mind? If you want a large and long beard your early neckline will help to keep things tidy while the rest of your beard bulks up. If you want a shorter beard like I have - waiting longer before making a neckline may serve you better. More mature hair growth attained after a few weeks will be easier to distinguish from young hair in later trims/neck shaves if you wait to make a neckline after at least 3 weeks. This was helpful for me.