Absolutely normal for a newbie, so don't panic!
But as a newbie, only three sets in, speed should not be your top priority. Mastering your Mix Ratio, Smile Lines and Filing Technique are more pressing issues than time right now.
Build your skill level in all aspects of the procedure and your time will automatically come down.
In the long run, completing a set of nail enhancements in 1 hour is a great aim to have, but it will take practice.
You're third set of enhancements took 3 hours 15 - by your tenth set you will see a HUGE difference in the amount of time it takes you.
If you are very keen to track your improvement in timing while you build your skill level, you could try timing each individual part of the process.
For example, if it takes an hour to complete a set of enhancements your time would be split up roughly as follows;
15-20 mins for P.R.E.P.
20-30 mins for Application (including Tipping or Form Fitting)
15-20 mins for Finishing
If you are trying for 2 hours, aim to double up these times.
At present, I imagine finishing is taking you an hour at least? The good news is this will change - and soon, provided you are getting the practice in. As your application becomes more precise your finishing will be less and less time consuming.
Remember, everyone goes through this in the beginning. The more practice you get, the faster you'll get faster!
Please don't get too hung up on the time it takes you, right now QUALITY is much more important than speed.
Good luck!!