Since deciding to convert last January I’ve struggled with similar issues.
I won’t be a full member of the church until at least next Easter. Yet my commitment is today in real time. If I am going to be a Catholic then the first step would seem to be adopting a Catholic lifestyle. Thus I started by taking up saying the Rosary daily and attending Mass 3 times a week months ago.
The Mass is entirely different from any worship service I have ever attended. I knew almost nothing about it at first and nobody really seemed interested in helping me understand it. I didn’t even know what the Holy Water Font was.
It hasn’t been easy. My solution has been to adopt what I can as I learn what each action means or am comfortable with that. Genuflecting at the pew came pretty early, as did crossing myself as I enter or leave the sanctuary.
Even now I do not have the Liturgy of the Eucharist memorized and can’t really participate in that part of the service. I just stand there respectfully and try to hear what is being recited and commit it to memory. As I become more comfortable that I understand each part I participate more fully.
As far as I can tell other folks don’t really care or notice. Oh I’m sure they would recognize me in a ‘oh yeah he’s been coming for months and doesn’t take communion’ sort of way, but the flip side of the ‘nobody is welcoming me’ coin is that ‘nobody is bothering me either’.
I arrive early for Mass and try to get in a good state of mind before the service starts and pray to be open and for God to help me get what I can out of each service. I believe that has helped me be less self-conscious than I might normally be and less worried about being phony or perceived as such by others.