Between second and third year is the usual time to do a placement year. However, if you can secure a placement between your first and second year, you may be able to talk to your university and take an interruption of studies to do a placement then- however, this would be entirely at your university's discretion.
It may also be difficult to find a company to take you at this stage.
If your course offers a formal placement year between years 2 and 3, there's unlikely to be much flexibility on this- but talk to your university and see what they say.