Show your gentlemen"ness" by asking her to lie down and enjoy first. Practice rhythmic licking for oral. make her feel comfortable and give her orgasm maybe 2 times before sticking in. Foreplay is to make her ready and make her comfortable with you.

when poking that time, try different position and gauge which one gives her the best experience. just repeat that good position. Different girl may enjoy different position more. some position might be painful some might be more enjoyable. Be nice and ask which she likes the most.

be persistent with shaking. you may do a deeper thrust to compensate or do at a bent angle to give more contact to her G spot.

Think of it as an endurance and tactful race rather than to sprint and win.