If you truly are a 3.0, or 3.5, or even low 4.0, don't be fooled you CAN hit a consistent kick serve. You cannot, and especially not a twist serve.
So, practice your top/slice serves. A fast one for your first serve, a slower spinnier one for your second serve.
Once you solidly play 4.0, it's time to work on your twist and kick serves.
You just don't have the consistent FAST swing speed up and outwards to hit kicks or twists.