You worked baseball, so influence from coaches on the sidelines shouldn't be a problem. Except .....they will look for weaknesses along the lines of being unsure lacking confidence.
You will have tunnel vision, it's a part of the growth process. I was a championship quarterback and grew into seeing more of the field as time went forward. I caught on faster than many I started wearing stripes with. You will grow to learn that you see far more than the running back with a ball in his hands. Study watch film, go on the Internet and watch you tube training videos.
One thing I have taught many new officials and crews I have evaluated. On kick offs eye the kick momentarily, if the ball goes high and in the air drop your eyes and head and officiate. Remember, watching the ball in flight is the fans job, not one football has ever been guilty of an illegal block, holding or any other foul .... But there are far too many eyes watching a brown football against a bright blue sky, that cannot tell you how # 56 got his leg broken by an illegal block.
If you have the wing, introduce yourself to the coach, practice your pre game and be clear concise and personable. Help the coach, give him numbers on fouls, explain the options on fouls. Be courteous yet let him know who's boss. You will grow comfortable, you will learn something new everyday. 40 years later you will still be learning.