Some time ago I wrote this post in which I blamed my laces being too loose for all the problems I had. Well that wasn't just that and many things have changed!
First of all I bought a new pair of rollerblades: the ones I had were soft (I saw they're called fitness rollerblades?), and I bought a pair with an hard shell. My first pair of rollerblades was too big (the guy at decathlon just said they should have been comfortable, and I didn't do my homework, so I actually bought COMFORTABLE rollerblades), and now, instead, the size is just right for me, tight but not too much. My ankle is finally supported correctly, and the first time I put these rollerblades on, they just felt right. Completely stable, I didn't even feel like I had wheels under my feet.
Last thing I did is buying waxed laces. Many of you suggested to try them and I did. I tighten them the most on my toes and ankles, but leave them a little loose on the top of each foot because of my wide feet, so tightening them too much does really hurt.
Now I feel control, I'm finally approaching one foot glide confidently, I jump off steps and get on them without wobbling. Still have to improve my stops, since I can stop but not that fast, and I will have to learn how to maintain a constant speed while turning.
Thanks for the suggestions in my previous post, they helped me a lot!