Hi Fenix
Yes that happens from time to time, if there is a que at yr broker they will execute in order as trades are taken and also (this is a 'private opinion' at some brokers according to yr account size, they have tiers)..
Most of us have more then 1 broker as brokers do not like to pay out - Some have 2 or 3 brokers and platforms. This is a trial and error discovery for you. People choose their broker for Specific reasons, my reasons may not suit you at all as we all have different trading patterns and different brokers offer different charts etc, therefore i doubt anyone will give you thence.
Good luck! name of their broker's,. You have to do that yourself, it is all part of the learning process and as you learn and carefully watch your Money Management it will give you a lot of experience.
Good luck!