You are repeating the same information again.
Various trees show Thomas Smith b Ireland 1835 with the information you keep repeating.
1851 Thomas Smith 13 yrs b Ireland with mother Jane and siblings - born abt 1838.
Published trees have Thomas Smith, convict, transported, 14 yrs on the Edwin Fox, 1858.
His conviction was manslaughter and newspaper reports from 1857 give his age as 21 yrs.
I have also seen reference to burglary as the crime though.
1861 2640/75/5
There is a Thomas Smith, 22 yrs b Ireland who is lodging with an Eagleton family.
Now this may not be the same Thomas from 1851 with mother Jane and siblings but you are not giving anything to support your repeated claims.
You need more evidence. Is there paperwork from Australia which have his date of birth and his parent details?
I don’t mean that his wife was Sarah and he had those children. I see that in the published trees. I mean paper work regarding him and his birth and parents.