Making a presentation to my Alma mater.

I graduated in May with a background in communications/PR/marketing and have gained experience just in the job hunt experience even though I haven't landed a job quite yet. There is a possibility I will be speaking/ giving a presentation at my Alma mater(different classes/groups such as frats & sororities) and other colleges for a start up (think of it as me presenting huttle to a class) My question is what is the best way to dress? For example
•would it be appropriate to wear a suit and tie (since I am representing a start-up​)
•or would it be appropriate wearing jeans and my college sweater to be most relatable to the students?
I ask because I know the first impression are always key and I've heard being relatable could be a factor. I appreciate any and all responses in advance.

I think in this situation a professional look is the best option. I think nice slacks, good dress shoes, and a button up shirt is a must. A blazer and tie can be added on if you think the audience will expect a more polished look, but you can't go wrong with nice slacks, shoes, and a shirt.

Let us know how it goes or if you have any other questions!