Ok, since this career seminar is going to be outdoor, I am quite sure it's going to get really hot, especially when it is in Singapore. A career seminar staple would be a button-down blouse, so I incorporated that into your outfit. Plus, as I know you personally for many years, your style is more of a rock-chic style, right? :) Since you are of the same age as me, you would not need to dress overly-formal, like blouse and pencil skirts, and it makes us look over-mature or older than our age. Since this is a "Career" seminar, you would want to project what your true self is, to give that best first impression.
As you can see, the denim jeans and leather-with-silver-studs sling-down bag contributes to the rocker-chic style of yours. Plus, I would think that you are going out with your friends probably after or before the seminar, so you can have an outfit transformation just by adding that denim gilet, to have a more casual feel. As for the shoes, I think we should go for comfort, so strapped sandals are the best. To emphasize your rock-chic style, you can choose to wear flat sandals in denim fabric with studs (on the right), or the one the one on the left which gives off a more formal feel (it's from outfittergirls). In addition, if you are afraid that it will get cold (which is kindda impossible), bring along a black blazer. The black blazer doesn't only protect you from the chills, it also adds to the formality of the outfit.
Hope you like this outfit, or has given you some ideas :)
Thank you dearies!