Local Prague friends (LPF) is amazing guys!
It's great value (super cheap) and offers an amazing experience. Words honestly cannot describe how much I recommended this.
To start with, LPF is a great customer oriented business. I messaged Kristian two weeks in advanced inquiring whether I can have a solo tour (as I am a solo traveller), and he replied right away saying yes.
After which, I got Katrin as my tour guide (great tourguide btw), and off we went on a great, amazing and informing journey. I personally love taking photos, and Katrin is very considerate, she patiently explained the history behind every structure, and also took me to many great hidden gems for photos. The walk was at a good pace (PLF will make sure they are going at a pace suitable for you). We travelled a long way around the castle, the lesser quarter and parts of the old town. Katrin even recommended me a traditional Czech dining restaurant afterwards (it was amazing, svikova is a must get).
Honestly, regardless of who you are, what you like and age, you will have a good time. But if you ever choose PLF, please expect to walk heaps (it is the point of the tour).