This runs a little counter to the whole idea of an A race and the structure associated with TrainerRoad but…
For a first time racer I think you’re best bet is not targeting it to win or even do well. Find a race that’s easy to get to and relatively low stakes (for you at least) and go do it.
I think many people put way too much emphasis on their results (myself included at times) in their races. You are essentially trying out a new hobby (racing is very different from riding) and you may or may not enjoy it. Get out there and do it - don’t put the pressure on yourself to do well. By all means you should race as hard as you can when you’re out there, but I would strongly encourage you not to plan an entire base/build/specialize cycle around a first race.
To pick a first race I’d say the ideal scenario would be a weekly training series (usually these run throughout the year, or at a minimum for the beginning portion of the season) and commit to yourself that you’re going to race the first four of them (or some other number that works for you). Go into the races without expectation of results, but expectations of learning and (hopefully) enjoying the test you’re putting yourself through. At that point you can evaluate the sport and whether you love it or hate it and possibly start thinking about peaking for certain events later in the season.
I think many new racers end up racing way less than they should because they build up the race in their head to the point that they get nervous and jittery and stressed out about every single race which leads to them not racing because of this extra mental stress. All of this adds up to create a negative experience so you end up seeing a lot of strong riders burning out from racing because of this after only a year or two.
Personally, when I’m lining up for my A race I’m a bundle of nerves - I love the challenge that comes with it but I’ve put a lot of effort into that specific peak so I still get stressed out. As a new racer I felt that way for every race, then only for B and C races, and now only for my A races. So it’s been a progression for me - but I definitely enjoy the experience a lot more when I’m out there to have fun and not care about results than when I’m there to win it (this is common even in the pros - see Landa, Mikel)