I am working on a model that predicts gestation period of new hires. By gestation period, I mean the period between when they completed their training and the time they start working on their first real live project. I have data for gestation period in months. I classified the time into two parts - "0 - 3 months" and "3 months or more". The purpose of the model is to reduce gestation time. It means the HR will recruit from only those colleges in which the students had performed well in the past and they went live early (i.e., low gestation time).
I have run logistic regression using gestation time as dependent variable - 1 for "0-3 months" and 0 for "3 months or more".
The independent variables are their college names, education qualification, specialization subject, graduation scores, training scores etc. Under the college name variable, I have data for 29 colleges. In other words, there are 29 options in this variable. How can I use this information as an independent variable in developing a predictive model? Should I take "1-29" options? Or is there any other way to group the data for this variable in logistic regression? Are there any other statistical technique you would suggest?