You should start your visa application process as soon as you have applied for a stay at Ulm University! Do not wait until you have received a formal acceptance letter, because:
- It might take up to six weeks to arrange a personal appointment with the nearest German embassy or consulate.
- It might take another 4-6 weeks until visa application has been approved.
In case you do not get your visa in time, you should not enter Germany on a tourist visa. It is not possible to convert it to a student visa after arrival!