The thing that I don't like about carbon offsets is the incentive to cheat. Green consumer buys carbon offset, company selling carbon offset pinky swears to offset carbon, but failing to do what was promised is unlikely to be caught, and is pure profit if they don't do it.
And they don't necessarily have to lie to do it. Take your growing trees example. They arrive at the carbon offset by saying that a tree takes X carbon, so Y trees will offset your carbon. They plant Y trees, and they are done.
However over half of trees planted in communities, will die within 1-2 years. (See https://www.state.sc.us/forest/urbsurv.htm for a source.) Based on conversations with people who planted trees for a living after clearcuts, in a wild forest setting the percentage loss is even higher for a combination of reasons from unreliable water to browsing by forest animals to a monoculture being vulnerable to disease. What incentive is there for the company planting the trees to come back in 5 years and see how many trees are still there? The higher the number, the better for them, checking just costs them money.
Moving on, are trees permanent CO2 storage? No. As forest fires around the world demonstrate, trees are only temporary storage. You don't control what will happen to those trees by mid-century and farther.
And all this assumes that there is no lying.
See https://www.csmonitor.com/Environment/2010/0420/Buying-carbo... for one of many examples where it turned out that there was lying.
So pay for your carbon offsets. It will soothe your conscience. It might even do some (probably temporary) good. But be aware that you're likely telling yourself a white lie if you think that they are real.