Gettting Back into Swimming -- Evaluating Fitness/Ability

Hi, I am 24 and, while I grew up swimming, it has been some time since I swam on a regular basis. I can remember some workouts/drills from middle/early high school, but much of that has faded from memory. For the last 2 weeks, I've been going 3x a week, swimming between 45 minutes and 1 hour at a time doing a mix of strokes, kick, and pull drills (w/ exception of butterfly -- I will attempt that when I'm a bit more fit.) I have remained in shape through other activities and I'm able to swim comfortably for 1 hour. I can feel myself getting stronger every time I hit the pool but I realize I have a ways to go. I was wondering if anyone has advice for evaluating my current swimming-fitness level. What are some helpful drills/measures of speed and endurance that I can use to evaluate how I might to improve? Any advice of how often and for how long I should train? Starter workouts would be helpful too, but I don't want to ask for too much :blush: I'd definitely like to be "better than average" for my age/gender. Any advice as to what that looks like and how to get me there? A bit more information: Age: 24 Height: 5'9" Weight: 143 lbs Occupation: grad student Thanks and best wishes