Using the Find Function

Hi! I have written the following script:

 number_trials=10000; 
 number_generations=21; 

 number_resistant_colonies_Darwin=zeros(number_trials,1); 
 final_number_bacteria=150*2^21;
 alpha=1e-8;

 for j=1:number_trials 

    NWild=zeros(1,number_generations+1);
    NMutant=zeros(1,number_generations+1);
    NWild(1)=150; 
    NMutant(1)=0; 
    for i=1:number_generations 
        New_born_mutants=poissrnd(alpha*NWild(i)); 
        NWild(i+1)=(2*NWild(i))-New_born_mutants; 
        NMutant(i+1)=(2* NMutant(i))+New_born_mutants;  
    end

    number_resistant_colonies_Darwin(j)=NMutant(end);
 end
generation_number=zeros(number_trials,1)

I would like to be able to record in which generation number the first mutant appeared and keep that generation number (for each trial) tabulated in the generation_number vector. I was looking into the find function but am uncertain about how to input it and also where in the nested for loop it would go. If there is an easier way than the find function, I would be happy to learn about that too! Thank you very much.

[Stephen23]

Follow-up / Duplicate which indicates the question has been resolved:

https://www.mathworks.com/matlabcentral/answers/400584-converting-a-1x1-vector-into-a-scalar-number