I am new to this arena so take my advice with a grain of salt. I am also 33 but in a much different situation. I get PA based on past experiences of not being able to perform. I can usually push through it, but sometimes I can't.
I have found that open communication works great. Now admittedly, I am married and have been with my wife for over 15 years so that is much different than just meeting someone. Obviously she can tell your interested if you get erections during making out sessions. Perhaps just opening the dialog saying your a little nervous, that way if you do fail then it isn't something she can start blaming herself for. If you don't bring it up, that will probably be the first thing that comes to her mind (I am guessing). Plus getting it off your chest may make you a bit more comfortable, and be able to relax and enjoy it.
That is the one thing that really confused my wife... we would make out and be intimate. And I would be very erect. Then we would start, and it would go away. I tried to explain that I was just anxious about not being able to perform, which kills an erection. At first she swore it was her, that I wasn't in to her or I was turning gay or something... but I think over time she has come to realize its just an anxiety problem.
Another thing that has helped in the past for me is visualization. I have found that in times when I think I may be losing it, if I slightly change positions where I can watch either what I am doing or how she is reacting, that is enough to help me push through it. This is probably something where YMMV definitely applies, but it works for me.
Finally, I have also found that while I do tend to start to lose an erection in the beginning, that if I keep going (and don't completely lose it) then I regain it to full status, and it is much more enjoyable when you can relax about it.
I don't know if any of this will be helpful to your situation, but at least I can post what has helped me in the past. Good luck!
) ? Is such fear normal, i mean i have phobia not PA...