Since you are young, and have had some lessons, you might do OK with this board and rig package, if you
have > 15 knots of wind most of the time.
What boards have you sailed when you took the lessons?
What size sails did you use?
The Seatrend is a nice board, but a fairly dated design.
It's from the "no nose" era, which didn't really work out all that well.
More modern boards are wider, more stable and plane significantly earlier, even
for a light weight young lady.
It's sort of about how steep do you wish to make your learning curve and how much
challenge are you willing to pursue.
The Seatrend you are looking at would not be the hardest board in the world to learn on,
but it's no where near the list of the easiest to learn on either.
Suggest you pass on this one and look for something a bit wider, and maybe around 120 liters.
You don't need all 120 liters just to float, @ 58 Kg/128 lbs., but a little extra buoyancy when you
are learning is a really good thing.