I’m early fifties, healthy and active. Had moderate Covid in early December and got our first Pfizer shots Wednesday. Felt very tired and headaches on Thursday into Friday. Probably about 20% of what I had experienced in December. My wife had mild Covid (lost taste and tired) and other than a sore arm experienced nothing from the shot. Both my teen children had Covid somewhere between our symptoms and just got their shots so have been monitoring them but so far so good. I’m not excited for my second shot. We’d debated not getting them but will be traveling internationally and expect them to be required.
Every booster shot improves immunity to some degree. That would be good to have, if you get exposed overseas, where health care is logistically difficult, and you might be more likely to encounter more challenging variants (like Brazil or South Africa).
You are likely to have less symptoms from the second shot, than from the first, because of your prior infection. For previously uninfected people, the second shot is more likely to produce worse symptoms.
Reportedly, tylenol is helpful with mild vaccine symptoms.
Also, if you skip your second shot, scheduling might be more difficult for a while (but in June we should be swimming in vaccine - enough for everyone).