1828 is fairly early for baptism records but you could just
be fortunate. Peter was a fairly unusual name at that time, unlike his father Patrick.
There is online baptism and marriage records on line for
Westmeath through a not for profit but fee paying websitewww.rootsireland.ie
If you are lucky you should find a Peter with a father Patrick on this website with a mother Jane Cullen. With both parents names you would get his siblings as well. Don't worry about the difference in ages from 1828/1834. The birth record will sort that out. Often people didn't really know their ages like we do today and most searches of Ireland include a +/- 5 years. Eg. in the Census
in 1901 a person is 53 and only 58 in 1911.
There were 17 Patrick Moran's in 1854, in 9 different parish's and 28 Cullen's but only 2 matching parish's, Drumraney & Kilcleagh.
Griffith Valuation 1854 www.askaboutireland.ie
He could also have been married previously if he was 34 as most Irish men married about age 20 but usually waited for
their own holding/land to rent. If his father had rented a large piece of land it could be divided but if he had an older brother that might of happened already.
What did he name his children as there is usually his father, brother & sister and mother's name plus her side.
Usually her father is the 2nd. son!