Many many moons ago, I started a USA Perimeter tour in San Diego and went northbound (NB) on the coast. While I did it, I would strongly recommend NOT doing it to anyone unless there was no other choice. I was a young and very strong rider of 23 (just graduated college). Riding NB does not lose "a bit of tailwind", it kills it, grinds in a tree chipper, and then pees on it. There were many days I was struggling in my lowest gears while the SB riders would LITERALLY coast by gleefully shouting "Great day for riding!". I became to really dislike SB riders and it affected my developing a bad "us vs them" mentality! Yet, they did nothing wrong. It was all because of the continual wind giving me difficulty. If you are thinking I was just a novice, that would be wrong. I had already done the TransAm and ridden across 7 states by this trip and easily averaged 6+k miles a year while in college so I was pretty strong.

While not every day was miserable, enough were to take a lot of the enjoyment out of it. Being a dumb Okie, I just hadn't thought/knew about taking the train up the coast, riding back south, and then take it up again to Seattle to continue on my way. In your case, I would highly recommend you start in Seattle (Vancouver if you have a passport), ride to Mexico, and then take the train back to Seattle for graduation. A compromise would be to start in San Fransisco and ride SB because it was along California coast where the winds were the worst. Then you could take the train back to SF and ride NB.

Additionally, along the actual coast, I kept riding over to the southbound side of the road to see the ocean only to have to ride back to the northbound side due to oncoming traffic. You would think being on the northbound side would not reduce the view that much but it really did surprisingly. If I rode SB, the scenery would have been much better.

Finally, I would guess the ratio was at least around 40:1 of SB to NB based on how many NB riders the SB riders said they saw that day. Yet, I only encountered a handful of NB riders during the 30 days it took to ride from Mexico to Vancouver. It would have been nice to be able to ride with others occasionally.

You asked if it really was that bad. Listen to people who have done what you are contemplating and don't repeat our mistakes! That is the sign of wisdom. You don't NEED to ride NB; you WANT to. You asked if it was really that bad. Yes, in my case it was. I was strong enough I could grind through it but it took a lot of enjoyment out of it. While I applaud the desire to ride to the graduation, I can not stress enough DO NOT DO IT. After all, why do it if you are not enjoying it?