A Catechumenate is one preparing for the sacrament of baptism. A Candidate is one that is baptised, but looking to join into full communion with the Catholic Church.
If you are a Catechumenate any sin that you have committed in your entire life will be washed clean in baptism. You will die in yourself and be reborn in Christ. It’s a new beginning. Your sin tally is erased and you start from there.
If you are a Candidate you will be encouraged to go to confession before you are confirmed to confess sins that you have committed since your baptism. Prior to this confession I would spend time in prayer examining your conscience and calling to mind the sins that you have committed since you were baptised, write them down if you have to and take the list into confession with you explaining to the priest that this is your first confession and you are a candidate (he can help if you if necessary).
Not being in full communion with the Church you aren’t obligated to follow the guidelines of fast and abstinence, however, as a future member of the Church it certainly wouldn’t hurt to begin living according to the teachings.
Remember there is a difference between fast and abstinence. Ash Wednesday and Good Friday are the only days where you practice both fast and abstinence, all other Fridays during Lent are simply days of abstinence.
Fasting = No snacks, only 1 full meal for the day, and 2 meals that are about half the size of the full meal.
Abstinence = No red meat, no chicken, beef, or pork. Fish, and by products like eggs or milk are ok.
In short the answer is no, you’re not obligated until you are a full member of the Church.