My experience in excel is less than 1 year but I have obsessed with numbers for my entire life. I would stay in front of a computer just to crunch the number out from problems. My strength will be in sorting out your data and key in data as customers' request. For further improvement, I would make it into a dashboard easier to be understand. I have a basic level with python for data analysis and data mining (numpy & pandas) that could do a further analysis for data.
Other than that, I own a firm for 2 years with a million turnover a year and I just quit recently. I believed my experiences in marketing and branding strategy could bring value to your business as that's my forte in business also.