Motosubatsu's answer stresses that
your first position after graduation doesn't mean your "stuck" doing that".
While this is true, I know plenty of SAP consultants and I know how difficult it was for those who wanted to switch jobs to find a position in a different technology. SAP is a world in itself and when you are considered an "SAP person", it's difficult to start doing something different. Your SAP experience won't mostly count as work related to other technologies, so it's possible that you will need to accept a junior position when you want to switch to a different technology in 1-3 years - unless you want to switch to a job of PM, process specialist or similar.
The good news is, however, at least in Europe SAP positions are currently really well paid. It's also super easy to find a job in SAP. So you need to consider what is most important for you: stability and a good salary or interesting tasks. If the former, stay in this technology and try to learn as much as you can. If the latter, start your job but simultaneously try to find a new position elsewhere.
It's important that you decide where you see yourself in several years. It's only after deciding that you can decide what to do now.