Yes, this is certainly possible; I am convinced my own mother had a glimpse of heaven's glory shortly before her own death. We read of Stephen (who was the first person to die for his faith in Christ) that as his enemies were stoning him to death he "looked up to heaven and saw the glory of God, and Jesus standing at the right hand of God" (Acts 7:55).
I hope you will thank God for the peace and joy your mother experienced as her death approached. But remember: These came not only from what was happening to her at that moment, but also from a lifetime of walking with Christ. She knew that God loved her, and she knew too that "neither death nor life ... nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord" (Romans 8:38-39).
For the Christian, death is not something to be feared (although we may, of course, shrink back from its pain). Instead, it is something to be welcomed with joy, because we know that death is not the end but is the gateway to eternal life with our Savior forever. Jesus' words about heaven are for every believer: "I am going there to prepare a place for you" (John 14:2).
Is your mother's faith in Christ also yours? Have you personally opened your own life to Christ, and are you seeking to live for Him every day? Someday you too will pass from this life–and may it be with joy and peace, because you know Christ.