Your first exam can be picked up from your TA either during their discussion section or office hours the week of Feb 2-6. Note that you will have to get your exam back from the TA for the discussion section in which you officially registered, which need not be the same as the TA name that you self-reported on your exam. If you're not sure which section you're registered in, check with the UCSD Registrar. If you are not sure the name of the TA who handles that section, you can find it here. If you are not sure when your TA's office hours are, you can find that here.
Remember that your grade for the course will be based on the numerical values (not letter equivalents) of your 3 exam scores. If we were to assign a grade based on the first exam alone, we would have used a scale like the following. You should use this scale only as a rough guide of how you are doing so far relative to your goals.
The final grade for the course will use finer increments to determine + and - letter categories as well.