Adela, welcome and congratulations.
Barre chords are a matter of practice. I think this is probably the single most discussed problem on this board. We ALL have or had problems with barre chords. I'm in the 'have' group.
Here are some suggestions others have made that helped me.
1. Don't squeeze, but pull your barring finger down. Squeezing too hard causes your hand to fatigue quickly.
2. Use good posture.
3. Place your left thumb just above the center of the neck and use it as a pivot point.
4. Anticipate the chord. Be thinking ahead of which chord is coming next and prepare yourself to play it.
5. Put your wrist far forward.
6. Use an exercise ball during the day to strengthen your fingers.
These are some things that have helped me. I still am poor at barre chords, but have gotten so that I can usually play F, F#m, and Bm without being too slow about it and without it sounding like completely dead strings. It's really just a matter of practice, practice, practice.
Best of luck to you. I look forward to seeing your post when you say you worked a barre chord into a song and are all excited about it.
- Zurf
Granted B chord amnesty by King of the Mutants (Long live the king).
If it comes from the heart and you add a few beers... it'll be awesome! - Mekidsmom
When in doubt ... hats. - B.G. Dude