I am not sure it is easy/possible to answer your question, so I will provide a slightly different perspective:
If you are a part of the top 20 school graduates, 90% will have a job within 3 months of graduation (August).... which is great. However, most of the reasons 90% will have jobs is because of the financial pressure and a need to have something. Then within the next 12 months, over half of these 90% will change jobs because the jobs they jumped into were not the right/best jobs for them. However, most people choose to have ANY job right away and then keep on looking for the ideal thing (or so they think).
I would say do not prepay your loan and keep as much cash as you can. There will be many unexpected expenses (trips to Dubai or Brazil with professors, car trouble, etc). You want to be insulated as much as possible. Also, most loans will require 2 applications (or rather a revision after the first year), so you can always apply for a higher/lower amount in year two, depending on your cash situation/stock market/interest rates/etc.
Congratulations on getting in and good luck!
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