I don't think precalculus was helpful at all for calculus (I took precalculus into AP calculus in high school). Assuming you are willing to put the effort in, I think you will be just fine with an online calculus course. Thankfully, Calculus I is probably the easiest of the three calculus courses you can take. It's a pretty 'friendly' course to ease into mathematics.
As said before, be sure to utilize online sources for teaching if you are finding concepts difficult. Wolfram Alpha, Khan Academy, etc are excellent for simplifying concepts and allowing you to master the material.
90% of mathematics is getting over the mentality that it's mathematics and is difficult.