Daughter was given half share in marital home but was pressed to sign it over to father and stepmother: is there any way this transfer can be rescinded?

When my parents divorced my mother gave her share of the marital home to be held in trust for me until my 18th birthday. My father subsequently remarried and my relationship with my stepmother has always been strained. Leading up to my 18th birthday my stepmother applied pressure to ensure that upon reaching majority I would sign over my share of the property to both her and my father. Her argument being that when they died I would inherit the entire property anyway and there wasn't much point me holding a share which I could demand at any time. The whole transfer process was arranged through their solicitor and I had no independent legal advice at any stage. Their solicitor seemed wary and asked me if I understood what I was doing and was I sure that I wanted to do this. In truth I was very naive and didn't really understand the implications of what I was doing. When the property was sold some years later my father was instructed by my stepmother not to divulge how much it was sold for. I have come to realise that my stepmother is a dishonest women and I now wonder where I stand legally with this matter.