Congrats Roger.
You are very lucky! Most of us old hands don't even have video of our first solo to remind us of that memorable day and how far we have come since.
Did the Tower know you were a first solo? I remember the tower guys and gals liked to know this so they don't try and request you to do something you might not be ready for.
Charles is a big unit, so there's no surpise about the ballooning (sorry Charles, hehehe!). That and the cool day, 1020 something QNH combination. The 1/2 rho in the lift formula bites again!
Centreline will come with pactice, confidence and discipline.
Now comes the second solo. Don't be too concerned if you fly like a complete chook and don't solo next time. This happens more than you think.
Good luck mate and all the best with the next one.
In-cog