It is good to bring forth the mind of repentance.
We all have been creating offenses since beginningless time and therefore need to learn to repent. There are many more forms of repentance besides becoming a vegetarian. You should also consider bowing to the Buddhas, meditate, or bow repentances etc.
I often advise my students to bow the Ten Thousand Buddhas Repentance because it is very effective. Or you could also bow the Great Compassion Repentance every day.
While being vegetarian is a good form of repentance, it tends to create pressure on family and friends because we are perceived as silently criticizing them. Therefore, those who first become vegetarian frequently encounter criticism and derision. It is a test of your sincerity. You learn to quietly endure criticism and opposition and then eventually, they will accept it. In the long haul, they eventually tend to admire your resolve.
Over all, to expect to repay off all your karmic debts is not feasible. Karmic retributions manifest so that we have the chance to repay our debts. To expect to be free of all debts is not that different from skipping town on your creditors: Buddhism does not advocate doing that.
Furthermore, you can use the Medicine Master Buddha Dharma as practiced in the Chinese tradition which is not available in Vietnamese temples. This is useful in cases where you wish to repay your debts quickly or those debts that are beyond your capacity to repay such as mental illnesses, possessions, etc. If you are interested, you can contact the temple directly to inquire.