Hi Claire ... I have got it wrong. It was an ELIZA, aged 18 years, not Elizabeth, that accompanied my 3xgm ALICE EDWARDS, on the voyage to NSW in 1839. So it seems there was another sister ELIZABETH EDWARDS who came with brother William in 1841 who was aged 17 years.
An Elizabeth Edwards, aged 21, married Richard Watson in 1843 ... but ELIZA fits the age not Elizabeth
... were they twins or Elizabeth fudged her age when she married Richard?