Select Range Macro Code

I have made a sheet where the user can insert/delete rows in a certain intervall of rows. The upper row is 17, that is I have named the cell "First" and then the last row "Last" and then I am using integers:

Dim intStartrow As Integer
Dim intLastrow As Integer
intStartrow = ActiveSheet.Range("First").Row + 1
intLastrow = ActiveSheet.Range("Last").Row - 1

So it is only possible to add/delete rows if the markerer is in between the above rows.

Now I would like to select the rows, from first to last. Since the rows are never the same, users add and delete rows all the time, I can not use

Range("A17:Z49").Select

Can I somehow make a range selection using the Integers, somethimg like

With ActiveSheet
Selection."intStartrow:intLastrow"
End With