Congrats on the maiden voyage. Was that truly average 3.2 kph or 3.2 knots?
After going aground did you just crank up the daggerboard and get out of the mud? Remember that your rudder
will be below your daggerboard if the daggerboard is cranked up and might drag on something. Also if you are in that shallow of water
then you can step off and push if the bottom is not too sticky.
I use a Garmin
and the cheaper ones seem to do all I need. I also have a handheld VHF radio
that I can keep next to me in the cockpit
to hear where traffic is. You can also call those big boats in the channel to see what they are up to.
If you haven't had a basic sailing course then I always recommend one and/or buy the book "Start Sailing Right!" and ask lots of questions.
Happy Sailing! She's a great little cruiser.