If you're talking about current events/experience in your life, I don't see anything wrong with using the present tense. I don't remember if that issue came up when I was writing mine, but it shouldn't be a problem. Also, always try to limit "was/am able to" unless it's really necessary because there are usually more concise and stronger ways to say the verb you are thinking of using (something that I struggle with a lot, hence the comment).
*Edit*: Just read my old PS to brush-up on these things, and I always used the past tense in mine because I referred to specific instances in the past (even concerning activities that I was currently involved in). But I think that this was just a stylistic thing and not representative of how PSs should be written in general.
